From ad7a5cca0e413e7337f3500fa2a154b5740a0ef9 Mon Sep 17 00:00:00 2001
From: liminge <liminge@andrew.cmu.edu>
Date: Sun, 28 Jan 2024 19:34:58 -0500
Subject: [PATCH 1/4] fix: use consistent predicate output format (#4112)

---
 src/predicate.ts       | 10 +++++-----
 test/predicate.test.ts | 32 ++++++++++++++++----------------
 2 files changed, 21 insertions(+), 21 deletions(-)

diff --git a/src/predicate.ts b/src/predicate.ts
index b981099e60..ea84bdf5bb 100644
--- a/src/predicate.ts
+++ b/src/predicate.ts
@@ -209,19 +209,19 @@ export function fieldFilterExpression(predicate: FieldPredicate, useInRange = tr
     : rawFieldExpr;
 
   if (isFieldEqualPredicate(predicate)) {
-    return `${fieldExpr}===${predicateValueExpr(predicate.equal, unit)}`;
+    return `${fieldExpr} === ${predicateValueExpr(predicate.equal, unit)}`;
   } else if (isFieldLTPredicate(predicate)) {
     const upper = predicate.lt;
-    return `${fieldExpr}<${predicateValueExpr(upper, unit)}`;
+    return `${fieldExpr} < ${predicateValueExpr(upper, unit)}`;
   } else if (isFieldGTPredicate(predicate)) {
     const lower = predicate.gt;
-    return `${fieldExpr}>${predicateValueExpr(lower, unit)}`;
+    return `${fieldExpr} > ${predicateValueExpr(lower, unit)}`;
   } else if (isFieldLTEPredicate(predicate)) {
     const upper = predicate.lte;
-    return `${fieldExpr}<=${predicateValueExpr(upper, unit)}`;
+    return `${fieldExpr} <= ${predicateValueExpr(upper, unit)}`;
   } else if (isFieldGTEPredicate(predicate)) {
     const lower = predicate.gte;
-    return `${fieldExpr}>=${predicateValueExpr(lower, unit)}`;
+    return `${fieldExpr} >= ${predicateValueExpr(lower, unit)}`;
   } else if (isFieldOneOfPredicate(predicate)) {
     return `indexof([${predicateValuesExpr(predicate.oneOf, unit).join(',')}], ${fieldExpr}) !== -1`;
   } else if (isFieldValidPredicate(predicate)) {
diff --git a/test/predicate.test.ts b/test/predicate.test.ts
index 208ec0f8f0..683dd1e49c 100644
--- a/test/predicate.test.ts
+++ b/test/predicate.test.ts
@@ -16,7 +16,7 @@ describe('filter', () => {
   const oneOfFilter = {field: 'color', oneOf: ['red', 'yellow']};
   const rangeFilter = {field: 'x', range: [0, 5]};
   const rangeSignalFilter = {field: 'x', range: {signal: 'range'}};
-  const exprFilter = 'datum["x"]===5';
+  const exprFilter = 'datum["x"] === 5';
   const lessThanEqualsFilter = {field: 'x', lte: 'z'};
   const validFilter: FieldValidPredicate = {field: 'x', valid: true};
 
@@ -96,27 +96,27 @@ describe('filter', () => {
   describe('expression', () => {
     it('should return a correct expression for an EqualFilter', () => {
       const expr = expression(null, {field: 'color', equal: 'red'});
-      expect(expr).toBe('datum["color"]==="red"');
+      expect(expr).toBe('datum["color"] === "red"');
     });
 
     it('should return correct expression for lessThan', () => {
       const expr = expression(null, {field: 'x', lt: 1});
-      expect(expr).toBe('datum["x"]<1');
+      expect(expr).toBe('datum["x"] < 1');
     });
 
     it('should return correct expression for greaterThan', () => {
       const expr = expression(null, {field: 'x', gt: 'aardvark'});
-      expect(expr).toBe('datum["x"]>"aardvark"');
+      expect(expr).toBe('datum["x"] > "aardvark"');
     });
 
     it('should return correct expression for lessThanEquals', () => {
       const expr = expression(null, {field: 'x', lte: 'zyzzyva'});
-      expect(expr).toBe('datum["x"]<="zyzzyva"');
+      expect(expr).toBe('datum["x"] <= "zyzzyva"');
     });
 
     it('should return correct expression for greaterThanEquals', () => {
       const expr = expression(null, {field: 'x', gte: 1});
-      expect(expr).toBe('datum["x"]>=1');
+      expect(expr).toBe('datum["x"] >= 1');
     });
 
     it('should return correct expression for valid', () => {
@@ -131,7 +131,7 @@ describe('filter', () => {
           month: 'January'
         }
       });
-      expect(expr).toBe('datum["date"]===time(datetime(2012, 0, 1, 0, 0, 0, 0))');
+      expect(expr).toBe('datum["date"] === time(datetime(2012, 0, 1, 0, 0, 0, 0))');
     });
 
     it('should return a correct expression for an EqualFilter with time unit and datetime object', () => {
@@ -143,7 +143,7 @@ describe('filter', () => {
         }
       });
       expect(expr).toBe(
-        'time(datetime(2012, month(datum["date"]), 1, 0, 0, 0, 0))===time(datetime(2012, 0, 1, 0, 0, 0, 0))'
+        'time(datetime(2012, month(datum["date"]), 1, 0, 0, 0, 0)) === time(datetime(2012, 0, 1, 0, 0, 0, 0))'
       );
     });
 
@@ -154,7 +154,7 @@ describe('filter', () => {
         equal: 'January'
       });
       expect(expr).toBe(
-        'time(datetime(2012, month(datum["date"]), 1, 0, 0, 0, 0))===time(datetime(2012, 0, 1, 0, 0, 0, 0))'
+        'time(datetime(2012, month(datum["date"]), 1, 0, 0, 0, 0)) === time(datetime(2012, 0, 1, 0, 0, 0, 0))'
       );
     });
 
@@ -165,7 +165,7 @@ describe('filter', () => {
           month: 'February'
         }
       });
-      expect(expr).toBe('datum["date"]<time(datetime(2012, 1, 1, 0, 0, 0, 0))');
+      expect(expr).toBe('datum["date"] < time(datetime(2012, 1, 1, 0, 0, 0, 0))');
     });
 
     it('should return a correct expression for an greaterThanFilter with time unit and datetime object', () => {
@@ -177,7 +177,7 @@ describe('filter', () => {
         }
       });
       expect(expr).toBe(
-        'time(datetime(2012, month(datum["date"]), 1, 0, 0, 0, 0))>time(datetime(2012, 0, 1, 0, 0, 0, 0))'
+        'time(datetime(2012, month(datum["date"]), 1, 0, 0, 0, 0)) > time(datetime(2012, 0, 1, 0, 0, 0, 0))'
       );
     });
 
@@ -188,7 +188,7 @@ describe('filter', () => {
         gte: 'January'
       });
       expect(expr).toBe(
-        'time(datetime(2012, month(datum["date"]), 1, 0, 0, 0, 0))>=time(datetime(2012, 0, 1, 0, 0, 0, 0))'
+        'time(datetime(2012, month(datum["date"]), 1, 0, 0, 0, 0)) >= time(datetime(2012, 0, 1, 0, 0, 0, 0))'
       );
     });
 
@@ -230,7 +230,7 @@ describe('filter', () => {
 
   it('generates expressions for composed filters', () => {
     let expr = expression(null, {not: {field: 'color', equal: 'red'}});
-    expect(expr).toBe('!(datum["color"]==="red")');
+    expect(expr).toBe('!(datum["color"] === "red")');
 
     expr = expression(null, {
       and: [
@@ -239,20 +239,20 @@ describe('filter', () => {
       ]
     });
 
-    expect(expr).toBe('(datum["color"]==="red") && (inrange(datum["x"], [0, 5]))');
+    expect(expr).toBe('(datum["color"] === "red") && (inrange(datum["x"], [0, 5]))');
 
     expr = expression(null, {
       and: [
         {field: 'color', oneOf: ['red', 'yellow']},
         {
-          or: [{field: 'x', range: [0, null]}, 'datum.price > 10', {not: 'datum["x"]===5'}]
+          or: [{field: 'x', range: [0, null]}, 'datum.price > 10', {not: 'datum["x"] === 5'}]
         }
       ]
     });
 
     expect(expr).toEqual(
       '(indexof(["red","yellow"], datum["color"]) !== -1) && ' +
-        '((datum["x"] >= 0) || (datum.price > 10) || (!(datum["x"]===5)))'
+        '((datum["x"] >= 0) || (datum.price > 10) || (!(datum["x"] === 5)))'
     );
   });
 

From f87403df742197ef147f76a16c36265b13ace651 Mon Sep 17 00:00:00 2001
From: liminge <liminge@andrew.cmu.edu>
Date: Sun, 28 Jan 2024 21:05:03 -0500
Subject: [PATCH 2/4] output single quotation marks instead of double quotation
 marks.

---
 src/predicate.ts       |  9 +++++---
 src/util.ts            | 10 +++++---
 test/predicate.test.ts | 52 +++++++++++++++++++++---------------------
 3 files changed, 39 insertions(+), 32 deletions(-)

diff --git a/src/predicate.ts b/src/predicate.ts
index ea84bdf5bb..c2b2833917 100644
--- a/src/predicate.ts
+++ b/src/predicate.ts
@@ -209,7 +209,8 @@ export function fieldFilterExpression(predicate: FieldPredicate, useInRange = tr
     : rawFieldExpr;
 
   if (isFieldEqualPredicate(predicate)) {
-    return `${fieldExpr} === ${predicateValueExpr(predicate.equal, unit)}`;
+    const equal = predicate.equal;
+    return `${fieldExpr} === ${predicateValueExpr(equal, unit)}`;
   } else if (isFieldLTPredicate(predicate)) {
     const upper = predicate.lt;
     return `${fieldExpr} < ${predicateValueExpr(upper, unit)}`;
@@ -223,9 +224,11 @@ export function fieldFilterExpression(predicate: FieldPredicate, useInRange = tr
     const lower = predicate.gte;
     return `${fieldExpr} >= ${predicateValueExpr(lower, unit)}`;
   } else if (isFieldOneOfPredicate(predicate)) {
-    return `indexof([${predicateValuesExpr(predicate.oneOf, unit).join(',')}], ${fieldExpr}) !== -1`;
+    const oneOf = predicate.oneOf;
+    return `indexof([${predicateValuesExpr(oneOf, unit).join(',')}], ${fieldExpr}) !== -1`;
   } else if (isFieldValidPredicate(predicate)) {
-    return fieldValidPredicate(fieldExpr, predicate.valid);
+    const valid = predicate.valid;
+    return fieldValidPredicate(fieldExpr, valid);
   } else if (isFieldRangePredicate(predicate)) {
     const {range} = predicate;
     const lower = isSignalRef(range) ? {signal: `${range.signal}[0]`} : range[0];
diff --git a/src/util.ts b/src/util.ts
index 832043a667..9330439282 100644
--- a/src/util.ts
+++ b/src/util.ts
@@ -288,13 +288,17 @@ export function accessPathWithDatum(path: string, datum = 'datum') {
  * @param datum The string to use for `datum`.
  */
 export function flatAccessWithDatum(path: string, datum: 'datum' | 'parent' | 'datum.datum' = 'datum') {
-  return `${datum}[${stringValue(splitAccessPath(path).join('.'))}]`;
+  return `${datum}[${doubleQuotes2Single(stringValue(splitAccessPath(path).join('.')))}]`;
 }
 
 function escapePathAccess(string: string) {
   return string.replace(/(\[|\]|\.|'|")/g, '\\$1');
 }
 
+function doubleQuotes2Single(string: string) {
+  return string.replace(/"/g, "'");
+}
+
 /**
  * Replaces path accesses with access to non-nested field.
  * For example, `foo["bar"].baz` becomes `foo\\.bar\\.baz`.
@@ -476,7 +480,7 @@ export function stringify(data: any) {
 
     if (node === undefined) return undefined;
     if (typeof node == 'number') return isFinite(node) ? '' + node : 'null';
-    if (typeof node !== 'object') return JSON.stringify(node);
+    if (typeof node !== 'object') return doubleQuotes2Single(JSON.stringify(node));
 
     let i, out;
     if (Array.isArray(node)) {
@@ -503,7 +507,7 @@ export function stringify(data: any) {
 
       if (!value) continue;
       if (out) out += ',';
-      out += JSON.stringify(key) + ':' + value;
+      out += doubleQuotes2Single(JSON.stringify(key)) + ':' + value;
     }
     seen.splice(seenIndex, 1);
     return `{${out}}`;
diff --git a/test/predicate.test.ts b/test/predicate.test.ts
index 683dd1e49c..d25cd8fd20 100644
--- a/test/predicate.test.ts
+++ b/test/predicate.test.ts
@@ -16,7 +16,7 @@ describe('filter', () => {
   const oneOfFilter = {field: 'color', oneOf: ['red', 'yellow']};
   const rangeFilter = {field: 'x', range: [0, 5]};
   const rangeSignalFilter = {field: 'x', range: {signal: 'range'}};
-  const exprFilter = 'datum["x"] === 5';
+  const exprFilter = "datum['x'] === 5";
   const lessThanEqualsFilter = {field: 'x', lte: 'z'};
   const validFilter: FieldValidPredicate = {field: 'x', valid: true};
 
@@ -96,32 +96,32 @@ describe('filter', () => {
   describe('expression', () => {
     it('should return a correct expression for an EqualFilter', () => {
       const expr = expression(null, {field: 'color', equal: 'red'});
-      expect(expr).toBe('datum["color"] === "red"');
+      expect(expr).toBe("datum['color'] === 'red'");
     });
 
     it('should return correct expression for lessThan', () => {
       const expr = expression(null, {field: 'x', lt: 1});
-      expect(expr).toBe('datum["x"] < 1');
+      expect(expr).toBe("datum['x'] < 1");
     });
 
     it('should return correct expression for greaterThan', () => {
       const expr = expression(null, {field: 'x', gt: 'aardvark'});
-      expect(expr).toBe('datum["x"] > "aardvark"');
+      expect(expr).toBe("datum['x'] > 'aardvark'");
     });
 
     it('should return correct expression for lessThanEquals', () => {
       const expr = expression(null, {field: 'x', lte: 'zyzzyva'});
-      expect(expr).toBe('datum["x"] <= "zyzzyva"');
+      expect(expr).toBe("datum['x'] <= 'zyzzyva'");
     });
 
     it('should return correct expression for greaterThanEquals', () => {
       const expr = expression(null, {field: 'x', gte: 1});
-      expect(expr).toBe('datum["x"] >= 1');
+      expect(expr).toBe("datum['x'] >= 1");
     });
 
     it('should return correct expression for valid', () => {
       const expr = expression(null, {field: 'x', valid: true});
-      expect(expr).toBe('isValid(datum["x"]) && isFinite(+datum["x"])');
+      expect(expr).toBe("isValid(datum['x']) && isFinite(+datum['x'])");
     });
 
     it('should return a correct expression for an EqualFilter with datetime object', () => {
@@ -131,7 +131,7 @@ describe('filter', () => {
           month: 'January'
         }
       });
-      expect(expr).toBe('datum["date"] === time(datetime(2012, 0, 1, 0, 0, 0, 0))');
+      expect(expr).toBe("datum['date'] === time(datetime(2012, 0, 1, 0, 0, 0, 0))");
     });
 
     it('should return a correct expression for an EqualFilter with time unit and datetime object', () => {
@@ -143,7 +143,7 @@ describe('filter', () => {
         }
       });
       expect(expr).toBe(
-        'time(datetime(2012, month(datum["date"]), 1, 0, 0, 0, 0)) === time(datetime(2012, 0, 1, 0, 0, 0, 0))'
+        "time(datetime(2012, month(datum['date']), 1, 0, 0, 0, 0)) === time(datetime(2012, 0, 1, 0, 0, 0, 0))"
       );
     });
 
@@ -154,7 +154,7 @@ describe('filter', () => {
         equal: 'January'
       });
       expect(expr).toBe(
-        'time(datetime(2012, month(datum["date"]), 1, 0, 0, 0, 0)) === time(datetime(2012, 0, 1, 0, 0, 0, 0))'
+        "time(datetime(2012, month(datum['date']), 1, 0, 0, 0, 0)) === time(datetime(2012, 0, 1, 0, 0, 0, 0))"
       );
     });
 
@@ -165,7 +165,7 @@ describe('filter', () => {
           month: 'February'
         }
       });
-      expect(expr).toBe('datum["date"] < time(datetime(2012, 1, 1, 0, 0, 0, 0))');
+      expect(expr).toBe("datum['date'] < time(datetime(2012, 1, 1, 0, 0, 0, 0))");
     });
 
     it('should return a correct expression for an greaterThanFilter with time unit and datetime object', () => {
@@ -177,7 +177,7 @@ describe('filter', () => {
         }
       });
       expect(expr).toBe(
-        'time(datetime(2012, month(datum["date"]), 1, 0, 0, 0, 0)) > time(datetime(2012, 0, 1, 0, 0, 0, 0))'
+        "time(datetime(2012, month(datum['date']), 1, 0, 0, 0, 0)) > time(datetime(2012, 0, 1, 0, 0, 0, 0))"
       );
     });
 
@@ -188,33 +188,33 @@ describe('filter', () => {
         gte: 'January'
       });
       expect(expr).toBe(
-        'time(datetime(2012, month(datum["date"]), 1, 0, 0, 0, 0)) >= time(datetime(2012, 0, 1, 0, 0, 0, 0))'
+        "time(datetime(2012, month(datum['date']), 1, 0, 0, 0, 0)) >= time(datetime(2012, 0, 1, 0, 0, 0, 0))"
       );
     });
 
     it('should return a correct expression for an InFilter', () => {
       const expr = expression(null, {field: 'color', oneOf: ['red', 'yellow']});
-      expect(expr).toBe('indexof(["red","yellow"], datum["color"]) !== -1');
+      expect(expr).toBe("indexof(['red','yellow'], datum['color']) !== -1");
     });
 
     it('should return a correct expression for a RangeFilter', () => {
       const expr = expression(null, {field: 'x', range: [0, 5]});
-      expect(expr).toBe('inrange(datum["x"], [0, 5])');
+      expect(expr).toBe("inrange(datum['x'], [0, 5])");
     });
 
     it('should return a correct expression for a RangeFilter with signal range', () => {
       const expr = expression(null, {field: 'x', range: {signal: 'r'}});
-      expect(expr).toBe('inrange(datum["x"], [r[0], r[1]])');
+      expect(expr).toBe("inrange(datum['x'], [r[0], r[1]])");
     });
 
     it('should return a correct expression for a RangeFilter with no lower bound', () => {
       const expr = expression(null, {field: 'x', range: [null, 5]});
-      expect(expr).toBe('datum["x"] <= 5');
+      expect(expr).toBe("datum['x'] <= 5");
     });
 
     it('should return a correct expression for a RangeFilter with no upper bound', () => {
       const expr = expression(null, {field: 'x', range: [0, null]});
-      expect(expr).toBe('datum["x"] >= 0');
+      expect(expr).toBe("datum['x'] >= 0");
     });
 
     it('should return true for a RangeFilter with no bound', () => {
@@ -223,14 +223,14 @@ describe('filter', () => {
     });
 
     it('should return a correct expression for an expression filter', () => {
-      const expr = expression(null, 'datum["x"]===5');
-      expect(expr).toBe('datum["x"]===5');
+      const expr = expression(null, "datum['x']===5");
+      expect(expr).toBe("datum['x']===5");
     });
   });
 
   it('generates expressions for composed filters', () => {
     let expr = expression(null, {not: {field: 'color', equal: 'red'}});
-    expect(expr).toBe('!(datum["color"] === "red")');
+    expect(expr).toBe("!(datum['color'] === 'red')");
 
     expr = expression(null, {
       and: [
@@ -239,27 +239,27 @@ describe('filter', () => {
       ]
     });
 
-    expect(expr).toBe('(datum["color"] === "red") && (inrange(datum["x"], [0, 5]))');
+    expect(expr).toBe("(datum['color'] === 'red') && (inrange(datum['x'], [0, 5]))");
 
     expr = expression(null, {
       and: [
         {field: 'color', oneOf: ['red', 'yellow']},
         {
-          or: [{field: 'x', range: [0, null]}, 'datum.price > 10', {not: 'datum["x"] === 5'}]
+          or: [{field: 'x', range: [0, null]}, 'datum.price > 10', {not: "datum['x'] === 5"}]
         }
       ]
     });
 
     expect(expr).toEqual(
-      '(indexof(["red","yellow"], datum["color"]) !== -1) && ' +
-        '((datum["x"] >= 0) || (datum.price > 10) || (!(datum["x"] === 5)))'
+      "(indexof(['red','yellow'], datum['color']) !== -1) && " +
+        "((datum['x'] >= 0) || (datum.price > 10) || (!(datum['x'] === 5)))"
     );
   });
 
   describe('fieldFilterExpression', () => {
     it('generates a range predicate using inequalities when useInRange=false', () => {
       const expr = fieldFilterExpression({field: 'x', range: [0, 5]}, false);
-      expect(expr).toBe('datum["x"] >= 0 && datum["x"] <= 5');
+      expect(expr).toBe("datum['x'] >= 0 && datum['x'] <= 5");
     });
   });
 });

From ccd43a2fbc89ba92386d4c74013fa01d0ebf9275 Mon Sep 17 00:00:00 2001
From: liminge <liminge@andrew.cmu.edu>
Date: Tue, 30 Jan 2024 19:13:23 -0500
Subject: [PATCH 3/4] swap single and double quotation marks in unit test part
 1.

---
 test/channeldef.test.ts                   | 12 ++++-----
 test/compile/axis/assemble.test.ts        |  2 +-
 test/compile/axis/encode.test.ts          |  8 +++---
 test/compile/axis/parse.test.ts           |  4 +--
 test/compile/data/calculate.test.ts       |  4 +--
 test/compile/data/density.test.ts         |  2 +-
 test/compile/data/extent.test.ts          |  2 +-
 test/compile/data/filter.test.ts          |  4 +--
 test/compile/data/filterinvalid.test.ts   |  4 +--
 test/compile/data/flatten.test.ts         |  2 +-
 test/compile/data/fold.test.ts            |  2 +-
 test/compile/data/impute.test.ts          |  2 +-
 test/compile/data/loess.test.ts           |  2 +-
 test/compile/data/lookup.test.ts          |  2 +-
 test/compile/data/pivot.test.ts           |  2 +-
 test/compile/data/quantile.test.ts        |  2 +-
 test/compile/data/sample.test.ts          |  2 +-
 test/compile/data/stack.test.ts           |  4 +--
 test/compile/data/timeunit.test.ts        |  6 ++---
 test/compile/data/window.test.ts          |  2 +-
 test/compile/format.test.ts               | 28 ++++++++++----------
 test/compile/header/assemble.test.ts      |  4 +--
 test/compile/legend/assemble.test.ts      |  2 +-
 test/compile/legend/encode.test.ts        |  6 ++---
 test/compile/mark/encode/valueref.test.ts |  2 +-
 test/compile/mark/mark.test.ts            |  8 +++---
 test/compile/mark/point.test.ts           |  8 +++---
 test/compile/mark/text.test.ts            |  6 ++---
 test/compile/scale/domain.test.ts         |  8 +++---
 test/compile/signal.test.ts               |  2 +-
 test/timeunit.test.ts                     | 32 +++++++++++------------
 test/util.test.ts                         | 14 +++++-----
 32 files changed, 95 insertions(+), 95 deletions(-)

diff --git a/test/channeldef.test.ts b/test/channeldef.test.ts
index c25574932c..5ed7ebd8a7 100644
--- a/test/channeldef.test.ts
+++ b/test/channeldef.test.ts
@@ -22,20 +22,20 @@ describe('fieldDef', () => {
     });
 
     it('should access flattened fields in expression', () => {
-      expect(vgField({field: 'foo.bar\\.baz'}, {expr: 'datum'})).toBe('datum["foo.bar.baz"]');
+      expect(vgField({field: 'foo.bar\\.baz'}, {expr: 'datum'})).toBe("datum['foo.bar.baz']");
     });
 
     it('should access argmin/argmax fields in expression', () => {
-      expect(vgField({aggregate: {argmin: 'b'}, field: 'a'})).toBe('argmin_b["a"]');
-      expect(vgField({aggregate: {argmax: 'b'}, field: 'a'})).toBe('argmax_b["a"]');
+      expect(vgField({aggregate: {argmin: 'b'}, field: 'a'})).toBe("argmin_b['a']");
+      expect(vgField({aggregate: {argmax: 'b'}, field: 'a'})).toBe("argmax_b['a']");
     });
 
     it('should support argmin/argmax field names with space', () => {
       expect(vgField({aggregate: {argmin: 'foo bar'}, field: 'bar baz'}, {expr: 'datum'})).toBe(
-        'datum["argmin_foo bar"]["bar baz"]'
+        "datum['argmin_foo bar']['bar baz']"
       );
       expect(vgField({aggregate: {argmax: 'foo bar'}, field: 'bar baz'}, {expr: 'datum'})).toBe(
-        'datum["argmax_foo bar"]["bar baz"]'
+        "datum['argmax_foo bar']['bar baz']"
       );
     });
 
@@ -48,7 +48,7 @@ describe('fieldDef', () => {
     });
 
     it('should support fields with space in datum', () => {
-      expect(vgField({field: 'foo bar'}, {expr: 'datum'})).toBe('datum["foo bar"]');
+      expect(vgField({field: 'foo bar'}, {expr: 'datum'})).toBe("datum['foo bar']");
     });
   });
 
diff --git a/test/compile/axis/assemble.test.ts b/test/compile/axis/assemble.test.ts
index 303ab1a62a..df3b01d88c 100644
--- a/test/compile/axis/assemble.test.ts
+++ b/test/compile/axis/assemble.test.ts
@@ -121,7 +121,7 @@ describe('compile/axis/assemble', () => {
 
     const axes = model.assembleAxes();
     expect(axes[1].encode.labels.update.text).toEqual({
-      signal: 'myFormat(datum.value, {"a":"b"})[0]'
+      signal: "myFormat(datum.value, {'a':'b'})[0]"
     });
   });
 });
diff --git a/test/compile/axis/encode.test.ts b/test/compile/axis/encode.test.ts
index 8b64e8b900..c2cbe61ba7 100644
--- a/test/compile/axis/encode.test.ts
+++ b/test/compile/axis/encode.test.ts
@@ -35,7 +35,7 @@ describe('compile/axis/encode', () => {
         config: {customFormatTypes: true}
       });
       const labels = encode.labels(model, 'x', {});
-      expect(labels.text.signal).toBe('customNumberFormat(datum.value, "abc")');
+      expect(labels.text.signal).toBe("customNumberFormat(datum.value, 'abc')");
     });
 
     it('applies custom format type without format', () => {
@@ -59,7 +59,7 @@ describe('compile/axis/encode', () => {
         config: {customFormatTypes: true, numberFormat: 'abc', numberFormatType: 'customNumberFormat'}
       });
       const labels = encode.labels(model, 'x', {});
-      expect(labels.text.signal).toBe('customNumberFormat(datum.value, "abc")');
+      expect(labels.text.signal).toBe("customNumberFormat(datum.value, 'abc')");
     });
 
     it('applies custom format type from a normalized stack', () => {
@@ -75,7 +75,7 @@ describe('compile/axis/encode', () => {
         }
       });
       const labels = encode.labels(model, 'x', {});
-      expect(labels.text.signal).toBe('customNumberFormat(datum.value, "abc")');
+      expect(labels.text.signal).toBe("customNumberFormat(datum.value, 'abc')");
     });
 
     it('applies custom timeFormatType from config', () => {
@@ -87,7 +87,7 @@ describe('compile/axis/encode', () => {
         config: {customFormatTypes: true, timeFormat: 'abc', timeFormatType: 'customTimeFormat'}
       });
       const labels = encode.labels(model, 'x', {});
-      expect(labels.text.signal).toBe('customTimeFormat(datum.value, "abc")');
+      expect(labels.text.signal).toBe("customTimeFormat(datum.value, 'abc')");
     });
 
     it('prefers timeUnit over timeFormatType from config', () => {
diff --git a/test/compile/axis/parse.test.ts b/test/compile/axis/parse.test.ts
index 29b437dc37..c243fc46b4 100644
--- a/test/compile/axis/parse.test.ts
+++ b/test/compile/axis/parse.test.ts
@@ -406,7 +406,7 @@ describe('Axis', () => {
       const axisComponent = parseUnitAxes(model);
       expect(axisComponent['x']).toHaveLength(1);
       expect(axisComponent['x'][0].get('format')).toEqual({
-        signal: 'timeUnitSpecifier(["quarter"], {"year-month":"%b %Y ","year-month-date":"%b %d, %Y "})'
+        signal: "timeUnitSpecifier(['quarter'], {'year-month':'%b %Y ','year-month-date':'%b %d, %Y '})"
       });
     });
 
@@ -446,7 +446,7 @@ describe('Axis', () => {
       const axisComponent = parseUnitAxes(model);
       expect(axisComponent['x']).toHaveLength(1);
       expect(axisComponent['x'][0].get('format')).toEqual({
-        signal: 'timeUnitSpecifier(["year","quarter","month"], {"year-month":"%b %Y ","year-month-date":"%b %d, %Y "})'
+        signal: "timeUnitSpecifier(['year','quarter','month'], {'year-month':'%b %Y ','year-month-date':'%b %d, %Y '})"
       });
     });
   });
diff --git a/test/compile/data/calculate.test.ts b/test/compile/data/calculate.test.ts
index 5ffefff77c..704413eb7f 100644
--- a/test/compile/data/calculate.test.ts
+++ b/test/compile/data/calculate.test.ts
@@ -28,7 +28,7 @@ describe('compile/data/calculate', () => {
       const nodes = assembleFromSortArray(model);
       expect(nodes).toEqual({
         type: 'formula',
-        expr: 'datum["a"]==="B" ? 0 : datum["a"]==="A" ? 1 : datum["a"]==="C" ? 2 : 3',
+        expr: "datum['a'] === 'B' ? 0 : datum[\'a\'] === 'A' ? 1 : datum['a'] === 'C' ? 2 : 3",
         as: 'x_a_sort_index'
       });
     });
@@ -64,7 +64,7 @@ describe('compile/data/calculate', () => {
       });
       const node = CalculateNode.parseAllForSortIndex(null, model) as CalculateNode;
       expect(node.hash()).toBe(
-        'Calculate {"as":"x_a_sort_index","calculate":"datum[\\"a\\"]===\\"B\\" ? 0 : datum[\\"a\\"]===\\"A\\" ? 1 : datum[\\"a\\"]===\\"C\\" ? 2 : 3"}'
+        "Calculate {'as':'x_a_sort_index','calculate':'datum[\'a\'] === \\'B\\' ? 0 : datum[\'a\'] === \\'A\\' ? 1 : datum[\'a\'] === \\'C\\' ? 2 : 3'}"
       );
     });
   });
diff --git a/test/compile/data/density.test.ts b/test/compile/data/density.test.ts
index 911510c88f..3f5e19457a 100644
--- a/test/compile/data/density.test.ts
+++ b/test/compile/data/density.test.ts
@@ -119,7 +119,7 @@ describe('compile/data/fold', () => {
         as: ['A', 'B']
       };
       const density = new DensityTransformNode(null, transform);
-      expect(density.hash()).toBe('DensityTransform {"as":["A","B"],"density":"v"}');
+      expect(density.hash()).toBe("DensityTransform {'as':['A','B'],'density':'v'}");
     });
   });
 
diff --git a/test/compile/data/extent.test.ts b/test/compile/data/extent.test.ts
index 94c31a1690..908e60adf6 100644
--- a/test/compile/data/extent.test.ts
+++ b/test/compile/data/extent.test.ts
@@ -36,7 +36,7 @@ describe('compile/data/extent', () => {
         param: 'A'
       };
       const extent = new ExtentTransformNode(null, transform);
-      expect(extent.hash()).toBe('ExtentTransform {"extent":"a","param":"A"}');
+      expect(extent.hash()).toBe("ExtentTransform {'extent':'a','param':'A'}");
     });
   });
 
diff --git a/test/compile/data/filter.test.ts b/test/compile/data/filter.test.ts
index 10cd9cc511..0003f95db8 100644
--- a/test/compile/data/filter.test.ts
+++ b/test/compile/data/filter.test.ts
@@ -63,7 +63,7 @@ describe('compile/data/filter', () => {
   describe('hash', () => {
     it('should generate the correct hash', () => {
       const filterNode = new FilterNode(null, null, {field: 'a', equal: {year: 2000}});
-      expect(filterNode.hash()).toBe('Filter datum["a"]===time(datetime(2000, 0, 1, 0, 0, 0, 0))');
+      expect(filterNode.hash()).toBe("Filter datum['a'] === time(datetime(2000, 0, 1, 0, 0, 0, 0))");
     });
   });
 
@@ -78,7 +78,7 @@ describe('compile/data/filter', () => {
   describe('assemble()', () => {
     it('converts expr in predicates correctly', () => {
       const node = new FilterNode(null, null, {field: 'foo', equal: {expr: 'bar'}});
-      expect(node.assemble().expr).toBe('datum["foo"]===bar');
+      expect(node.assemble().expr).toBe("datum['foo'] === bar");
     });
   });
 });
diff --git a/test/compile/data/filterinvalid.test.ts b/test/compile/data/filterinvalid.test.ts
index 3eaddce808..7a97d556ab 100644
--- a/test/compile/data/filterinvalid.test.ts
+++ b/test/compile/data/filterinvalid.test.ts
@@ -99,7 +99,7 @@ describe('compile/data/filterinvalid', () => {
 
         expect(parse(model).assemble()).toEqual({
           type: 'filter',
-          expr: 'isValid(datum["foo"]) && isFinite(+datum["foo"])'
+          expr: "isValid(datum['foo']) && isFinite(+datum['foo'])"
         });
       });
 
@@ -113,7 +113,7 @@ describe('compile/data/filterinvalid', () => {
 
         expect(parse(model).assemble()).toEqual({
           type: 'filter',
-          expr: 'isValid(datum["foo.bar"]) && isFinite(+datum["foo.bar"])'
+          expr: "isValid(datum['foo.bar']) && isFinite(+datum['foo.bar'])"
         });
       });
     });
diff --git a/test/compile/data/flatten.test.ts b/test/compile/data/flatten.test.ts
index 9ae60209b7..df678ed60b 100644
--- a/test/compile/data/flatten.test.ts
+++ b/test/compile/data/flatten.test.ts
@@ -78,7 +78,7 @@ describe('compile/data/flatten', () => {
           flatten: ['a', 'b']
         };
         const flatten = new FlattenTransformNode(null, transform);
-        expect(flatten.hash()).toBe('FlattenTransform {"as":["a","b"],"flatten":["a","b"]}');
+        expect(flatten.hash()).toBe("FlattenTransform {'as':['a','b'],'flatten':['a','b']}");
       });
     });
   });
diff --git a/test/compile/data/fold.test.ts b/test/compile/data/fold.test.ts
index adb5338e91..a4a05f3b24 100644
--- a/test/compile/data/fold.test.ts
+++ b/test/compile/data/fold.test.ts
@@ -80,7 +80,7 @@ describe('compile/data/fold', () => {
         as: ['A', 'B']
       };
       const fold = new FoldTransformNode(null, transform);
-      expect(fold.hash()).toBe('FoldTransform {"as":["A","B"],"fold":["a","b"]}');
+      expect(fold.hash()).toBe("FoldTransform {'as':['A','B'],'fold':['a','b']}");
     });
   });
 
diff --git a/test/compile/data/impute.test.ts b/test/compile/data/impute.test.ts
index 8209a53555..1afa2fed53 100644
--- a/test/compile/data/impute.test.ts
+++ b/test/compile/data/impute.test.ts
@@ -210,7 +210,7 @@ describe('compile/data/impute', () => {
         value: 200
       };
       const impute = new ImputeNode(null, transform);
-      expect(impute.hash()).toBe('Impute {"impute":"y","key":"x","method":"value","value":200}');
+      expect(impute.hash()).toBe("Impute {'impute':'y','key':'x','method':'value','value':200}");
     });
   });
 
diff --git a/test/compile/data/loess.test.ts b/test/compile/data/loess.test.ts
index 9eee9116c1..7e94a603cd 100644
--- a/test/compile/data/loess.test.ts
+++ b/test/compile/data/loess.test.ts
@@ -104,7 +104,7 @@ describe('compile/data/fold', () => {
         as: ['A', 'B']
       };
       const loess = new LoessTransformNode(null, transform);
-      expect(loess.hash()).toBe('LoessTransform {"as":["A","B"],"loess":"y","on":"x"}');
+      expect(loess.hash()).toBe("LoessTransform {'as':['A','B'],'loess':'y','on':'x'}");
     });
   });
 
diff --git a/test/compile/data/lookup.test.ts b/test/compile/data/lookup.test.ts
index 24ce16b45a..8ff26b07ba 100644
--- a/test/compile/data/lookup.test.ts
+++ b/test/compile/data/lookup.test.ts
@@ -205,7 +205,7 @@ describe('compile/data/lookup', () => {
       lookup.assemble();
 
       expect(lookup.hash()).toBe(
-        'Lookup {"secondary":"lookup_0","transform":{"as":"lookedup","from":{"data":{"url":"data/lookup_people.csv"},"key":"name"},"lookup":"person"}}'
+        "Lookup {'secondary':'lookup_0','transform':{'as':'lookedup','from':{'data':{'url':'data/lookup_people.csv'},'key':'name'},'lookup':'person'}}"
       );
     });
   });
diff --git a/test/compile/data/pivot.test.ts b/test/compile/data/pivot.test.ts
index 8b4b77d96f..6b756735f7 100644
--- a/test/compile/data/pivot.test.ts
+++ b/test/compile/data/pivot.test.ts
@@ -70,7 +70,7 @@ describe('compile/data/pivot', () => {
       value: 'b'
     };
     const pivot = new PivotTransformNode(null, transform);
-    expect(pivot.hash()).toBe('PivotTransform {"pivot":"a","value":"b"}');
+    expect(pivot.hash()).toBe("PivotTransform {'pivot':'a','value':'b'}");
   });
 
   describe('clone', () => {
diff --git a/test/compile/data/quantile.test.ts b/test/compile/data/quantile.test.ts
index 4c422eff59..350509962a 100644
--- a/test/compile/data/quantile.test.ts
+++ b/test/compile/data/quantile.test.ts
@@ -93,7 +93,7 @@ describe('compile/data/fold', () => {
         as: ['A', 'B']
       };
       const quantile = new QuantileTransformNode(null, transform);
-      expect(quantile.hash()).toBe('QuantileTransform {"as":["A","B"],"quantile":"x"}');
+      expect(quantile.hash()).toBe("QuantileTransform {'as':['A','B'],'quantile':'x'}");
     });
   });
 
diff --git a/test/compile/data/sample.test.ts b/test/compile/data/sample.test.ts
index 5216a6b19e..5ebe4a1e4a 100644
--- a/test/compile/data/sample.test.ts
+++ b/test/compile/data/sample.test.ts
@@ -25,7 +25,7 @@ describe('compile/data/sample', () => {
     describe('producedFields', () => {
       it('should generate the correct hash', () => {
         const sample = new SampleTransformNode(null, transform);
-        expect(sample.hash()).toBe('SampleTransform {"sample":500}');
+        expect(sample.hash()).toBe("SampleTransform {'sample':500}");
       });
 
       it('should produce different hashes for different samples', () => {
diff --git a/test/compile/data/stack.test.ts b/test/compile/data/stack.test.ts
index 11d0d1f04e..aafbbe0d9a 100644
--- a/test/compile/data/stack.test.ts
+++ b/test/compile/data/stack.test.ts
@@ -202,7 +202,7 @@ describe('compile/data/stack', () => {
       expect(assemble(model)).toEqual([
         {
           type: 'formula',
-          expr: '0.5*datum["bin_maxbins_10_b"]+0.5*datum["bin_maxbins_10_b_end"]',
+          expr: "0.5*datum['bin_maxbins_10_b']+0.5*datum['bin_maxbins_10_b_end']",
           as: 'bin_maxbins_10_b_mid'
         },
         {
@@ -350,7 +350,7 @@ describe('compile/data/stack', () => {
       });
       const stack = StackNode.makeFromEncoding(null, model);
       expect(stack.hash()).toBe(
-        'Stack {"as":["sum_a_start","sum_a_end"],"dimensionFieldDefs":[{"field":"b","type":"nominal"}],"facetby":[],"impute":false,"offset":"zero","sort":{"field":["c"],"order":["ascending"]},"stackField":"sum_a","stackby":["c"]}'
+        "Stack {'as':['sum_a_start','sum_a_end'],'dimensionFieldDefs':[{'field':'b','type':'nominal'}],'facetby':[],'impute':false,'offset':'zero','sort':{'field':['c'],'order':['ascending']},'stackField':'sum_a','stackby':['c']}"
       );
     });
 
diff --git a/test/compile/data/timeunit.test.ts b/test/compile/data/timeunit.test.ts
index 85cce49580..e0e8456ab4 100644
--- a/test/compile/data/timeunit.test.ts
+++ b/test/compile/data/timeunit.test.ts
@@ -247,7 +247,7 @@ describe('compile/data/timeunit', () => {
       });
       const timeUnitNode = TimeUnitNode.makeFromEncoding(null, model);
       expect(timeUnitNode.hash()).toBe(
-        'TimeUnit {"{\\"as\\":\\"month_a\\",\\"field\\":\\"a\\",\\"timeUnit\\":{\\"unit\\":\\"month\\"}}":{"as":"month_a","field":"a","timeUnit":{"unit":"month"}}}'
+        "TimeUnit {'{'as':'month_a','field':'a','timeUnit':{'unit':'month'}}':{'as':'month_a','field':'a','timeUnit':{'unit':'month'}}}"
       );
     });
     it('should generate the correct hash for bar', () => {
@@ -260,7 +260,7 @@ describe('compile/data/timeunit', () => {
       });
       const timeUnitNode = TimeUnitNode.makeFromEncoding(null, model);
       expect(timeUnitNode.hash()).toBe(
-        'TimeUnit {"{\\"as\\":\\"month_a\\",\\"field\\":\\"a\\",\\"timeUnit\\":{\\"unit\\":\\"month\\"}}":{"as":"month_a","field":"a","timeUnit":{"unit":"month"}}}'
+        "TimeUnit {'{'as':'month_a','field':'a','timeUnit':{'unit':'month'}}':{'as':'month_a','field':'a','timeUnit':{'unit':'month'}}}"
       );
     });
 
@@ -274,7 +274,7 @@ describe('compile/data/timeunit', () => {
       });
       const timeUnitNode = TimeUnitNode.makeFromEncoding(null, model);
       expect(timeUnitNode.hash()).toBe(
-        'TimeUnit {"{\\"as\\":\\"utcmonth_step_10_a\\",\\"field\\":\\"a\\",\\"timeUnit\\":{\\"step\\":10,\\"unit\\":\\"month\\",\\"utc\\":true}}":{"as":"utcmonth_step_10_a","field":"a","timeUnit":{"step":10,"unit":"month","utc":true}}}'
+        "TimeUnit {'{'as':'utcmonth_step_10_a','field':'a','timeUnit':{'step':10,'unit':'month','utc':true}}':{'as':'utcmonth_step_10_a','field':'a','timeUnit':{'step':10,'unit':'month','utc':true}}}"
       );
     });
   });
diff --git a/test/compile/data/window.test.ts b/test/compile/data/window.test.ts
index 49151ed6a8..6a10c409ea 100644
--- a/test/compile/data/window.test.ts
+++ b/test/compile/data/window.test.ts
@@ -190,7 +190,7 @@ describe('compile/data/window', () => {
     const window = new WindowTransformNode(null, transform);
     const hash = window.hash();
     expect(hash).toBe(
-      'WindowTransform {"frame":[null,0],"groupby":["f"],"ignorePeers":false,"sort":[{"field":"f","order":"ascending"}],"window":[{"as":"ordered_row_number","op":"row_number"}]}'
+      "WindowTransform {'frame':[null,0],'groupby':['f'],'ignorePeers':false,'sort':[{'field':'f','order':'ascending'}],'window':[{'as':'ordered_row_number','op':'row_number'}]}"
     );
   });
 });
diff --git a/test/compile/format.test.ts b/test/compile/format.test.ts
index ada7be09f4..5521490f93 100644
--- a/test/compile/format.test.ts
+++ b/test/compile/format.test.ts
@@ -20,7 +20,7 @@ describe('Format', () => {
         rawTimeFormat: defaultConfig.timeFormat
       });
       expect(expression).toBe(
-        'timeFormat(datum["month_a"], timeUnitSpecifier(["month"], {"year-month":"%b %Y ","year-month-date":"%b %d, %Y "}))'
+        "timeFormat(datum['month_a'], timeUnitSpecifier(['month'], {'year-month':'%b %Y ','year-month-date':'%b %d, %Y '}))"
       );
     });
 
@@ -32,7 +32,7 @@ describe('Format', () => {
         format: '%Y',
         rawTimeFormat: defaultConfig.timeFormat
       });
-      expect(expression).toBe(`timeFormat(datum["yearmonth_a"], '%Y')`);
+      expect(expression).toBe(`timeFormat(datum['yearmonth_a'], '%Y')`);
     });
 
     it('should get the right time expression for quarter', () => {
@@ -43,7 +43,7 @@ describe('Format', () => {
         rawTimeFormat: defaultConfig.timeFormat
       });
       expect(expression).toBe(
-        'timeFormat(datum["quarter_a"], timeUnitSpecifier(["quarter"], {"year-month":"%b %Y ","year-month-date":"%b %d, %Y "}))'
+        "timeFormat(datum['quarter_a'], timeUnitSpecifier(['quarter'], {'year-month':'%b %Y ','year-month-date':'%b %d, %Y '}))"
       );
     });
 
@@ -54,7 +54,7 @@ describe('Format', () => {
         rawTimeFormat: defaultConfig.timeFormat
       });
       expect(expression).toBe(
-        'timeFormat(datum["data"], timeUnitSpecifier(["year","quarter"], {"year-month":"%b %Y ","year-month-date":"%b %d, %Y "}))'
+        "timeFormat(datum['data'], timeUnitSpecifier(['year','quarter'], {'year-month':'%b %Y ','year-month-date':'%b %d, %Y '}))"
       );
     });
 
@@ -67,7 +67,7 @@ describe('Format', () => {
         rawTimeFormat: defaultConfig.timeFormat,
         isUTCScale: true
       });
-      expect(expression).toBe(`utcFormat(datum["yearmonth_a"], '%Y')`);
+      expect(expression).toBe(`utcFormat(datum['yearmonth_a'], '%Y')`);
     });
 
     it('should get the right time expression for with a custom timeFormatType', () => {
@@ -77,7 +77,7 @@ describe('Format', () => {
         format: '%Y',
         formatType: 'customFormat'
       });
-      expect(expression).toBe(`customFormat(datum["a"], '%Y')`);
+      expect(expression).toBe(`customFormat(datum['a'], '%Y')`);
     });
 
     it('should prefer timeUnit over timeFormatType', () => {
@@ -88,7 +88,7 @@ describe('Format', () => {
         timeUnit: 'date',
         formatType: 'customFormat'
       });
-      expect(expression).toBe(`timeFormat(datum["date_a"], '%Y')`);
+      expect(expression).toBe(`timeFormat(datum['date_a'], '%Y')`);
     });
   });
 
@@ -101,7 +101,7 @@ describe('Format', () => {
     it('returns the the formatted timeUnitExpression', () => {
       const formatted = timeFormat({timeUnit: 'date', config: {}});
       expect(formatted).toEqual({
-        signal: 'timeUnitSpecifier(["date"], {"year-month":"%b %Y ","year-month-date":"%b %d, %Y "})'
+        signal: "timeUnitSpecifier(['date'], {'year-month':'%b %Y ','year-month-date':'%b %d, %Y '})"
       });
     });
 
@@ -167,7 +167,7 @@ describe('Format', () => {
           config: {}
         })
       ).toEqual({
-        signal: 'format(parent["foo"], ".2f")'
+        signal: "format(parent['foo'], '.2f')"
       });
     });
 
@@ -182,7 +182,7 @@ describe('Format', () => {
         })
       ).toEqual({
         signal:
-          '!isValid(parent["bin_maxbins_10_foo"]) || !isFinite(+parent["bin_maxbins_10_foo"]) ? "null" : format(parent["bin_maxbins_10_foo"], "abc") + " – " + format(parent["bin_maxbins_10_foo_end"], "abc")'
+          "!isValid(parent['bin_maxbins_10_foo']) || !isFinite(+parent['bin_maxbins_10_foo']) ? 'null' : format(parent['bin_maxbins_10_foo'], 'abc') + ' – ' + format(parent['bin_maxbins_10_foo_end'], 'abc')"
       });
     });
 
@@ -196,7 +196,7 @@ describe('Format', () => {
           config: {}
         })
       ).toEqual({
-        signal: 'format(200, ".2f")'
+        signal: "format(200, '.2f')"
       });
     });
 
@@ -238,7 +238,7 @@ describe('Format', () => {
           config: {timeFormat: 'abc', timeFormatType: 'customFormatter', customFormatTypes: true}
         })
       ).toEqual({
-        signal: 'customFormatter(parent["date"], "abc")'
+        signal: "customFormatter(parent['date'], 'abc')"
       });
     });
 
@@ -278,7 +278,7 @@ describe('Format', () => {
           }
         })
       ).toEqual({
-        signal: 'customFormatter(200, "abc")'
+        signal: "customFormatter(200, 'abc')"
       });
     });
   });
@@ -335,7 +335,7 @@ describe('Format', () => {
         false
       );
       expect(format).toEqual({
-        signal: 'timeUnitSpecifier(["hours"], {"year-month":"%b %Y ","year-month-date":"%b %d, %Y "})'
+        signal: "timeUnitSpecifier(['hours'], {'year-month':'%b %Y ','year-month-date':'%b %d, %Y '})"
       });
     });
 
diff --git a/test/compile/header/assemble.test.ts b/test/compile/header/assemble.test.ts
index 25fc13103f..1227117935 100644
--- a/test/compile/header/assemble.test.ts
+++ b/test/compile/header/assemble.test.ts
@@ -99,7 +99,7 @@ describe('compile/header/index', () => {
       model.parseAxesAndHeaders();
 
       const rowHeaderGroups = assembleHeaderGroups(model, 'row');
-      expect(rowHeaderGroups[0].sort.field).toBe('datum["min_d"]');
+      expect(rowHeaderGroups[0].sort.field).toBe("datum['min_d']");
     });
   });
 
@@ -320,7 +320,7 @@ describe('compile/header/index', () => {
         }
       );
 
-      expect(title.text).toEqual({signal: 'parent["foo"][0]'});
+      expect(title.text).toEqual({signal: "parent['foo'][0]"});
     });
   });
 });
diff --git a/test/compile/legend/assemble.test.ts b/test/compile/legend/assemble.test.ts
index e13affea92..fab96bf1f8 100644
--- a/test/compile/legend/assemble.test.ts
+++ b/test/compile/legend/assemble.test.ts
@@ -48,7 +48,7 @@ describe('legend/assemble', () => {
 
     const legends = model.assembleLegends();
     expect(legends[0].encode.labels.update.text).toEqual({
-      signal: 'myFormat(datum.value, {"a":"b"})[0]'
+      signal: "myFormat(datum.value, {'a':'b'})[0]"
     });
   });
 
diff --git a/test/compile/legend/encode.test.ts b/test/compile/legend/encode.test.ts
index d36bbaae7f..71284270d1 100644
--- a/test/compile/legend/encode.test.ts
+++ b/test/compile/legend/encode.test.ts
@@ -163,7 +163,7 @@ describe('compile/legend', () => {
         {},
         {fieldOrDatumDef: fieldDef, model, channel: COLOR, legendCmpt: symbolLegend, legendType: 'symbol'}
       );
-      expect(label.text).toEqual({signal: 'customDateFormat(datum.value, "abc")'});
+      expect(label.text).toEqual({signal: "customDateFormat(datum.value, 'abc')"});
     });
   });
 
@@ -183,7 +183,7 @@ describe('compile/legend', () => {
       {},
       {fieldOrDatumDef: fieldDef, model, channel: COLOR, legendCmpt: symbolLegend, legendType: 'symbol'}
     );
-    expect(label.text).toEqual({signal: 'customDateFormat(datum.value, "abc")'});
+    expect(label.text).toEqual({signal: "customDateFormat(datum.value, 'abc')"});
   });
 
   it('returns correct expression for custom format Type from config.timeFormatType', () => {
@@ -202,7 +202,7 @@ describe('compile/legend', () => {
       {},
       {fieldOrDatumDef: fieldDef, model, channel: COLOR, legendCmpt: symbolLegend, legendType: 'symbol'}
     );
-    expect(label.text).toEqual({signal: 'customDateFormat(datum.value, "abc")'});
+    expect(label.text).toEqual({signal: "customDateFormat(datum.value, 'abc')"});
   });
 
   it('prefers timeUnit over config.timeFormatType', () => {
diff --git a/test/compile/mark/encode/valueref.test.ts b/test/compile/mark/encode/valueref.test.ts
index e662f3e7c8..0812d65e52 100644
--- a/test/compile/mark/encode/valueref.test.ts
+++ b/test/compile/mark/encode/valueref.test.ts
@@ -70,7 +70,7 @@ describe('compile/mark/encode/valueref', () => {
         scale: undefined,
         defaultRef
       });
-      expect(ref).toEqual({signal: 'scale("x", 0.5 * datum["bin_start"] + 0.5 * datum["bin_end"])'});
+      expect(ref).toEqual({signal: "scale('x', 0.5 * datum['bin_start'] + 0.5 * datum['bin_end'])"});
     });
   });
 
diff --git a/test/compile/mark/mark.test.ts b/test/compile/mark/mark.test.ts
index 00815dedc2..b32c4707e5 100644
--- a/test/compile/mark/mark.test.ts
+++ b/test/compile/mark/mark.test.ts
@@ -336,7 +336,7 @@ describe('Mark', () => {
         }
       });
       expect(getSort(model)).toEqual({
-        field: ['datum["year"]'],
+        field: ["datum['year']"],
         order: ['ascending']
       });
     });
@@ -375,7 +375,7 @@ describe('Mark', () => {
         }
       });
       expect(getSort(model)).toEqual({
-        field: 'datum["bin_maxbins_10_IMDB_Rating"]'
+        field: "datum['bin_maxbins_10_IMDB_Rating']"
       });
     });
 
@@ -416,7 +416,7 @@ describe('Mark', () => {
         }
       });
       expect(getSort(model)).toEqual({
-        field: 'datum["x_Name_sort_index"]'
+        field: "datum['x_Name_sort_index']"
       });
     });
 
@@ -434,7 +434,7 @@ describe('Mark', () => {
         }
       });
       expect(getSort(model)).toEqual({
-        field: 'datum["Score"]'
+        field: "datum['Score']"
       });
     });
 
diff --git a/test/compile/mark/point.test.ts b/test/compile/mark/point.test.ts
index ba91472b95..c2425ee62a 100644
--- a/test/compile/mark/point.test.ts
+++ b/test/compile/mark/point.test.ts
@@ -104,7 +104,7 @@ describe('Mark: Point', () => {
 
     const props = point.encodeEntry(model);
 
-    expect(props.x).toEqual({signal: 'scale("x", 0.5 * datum["a_start"] + 0.5 * datum["a_end"])'});
+    expect(props.x).toEqual({signal: "scale('x', 0.5 * datum['a_start'] + 0.5 * datum['a_end'])"});
   });
 
   it('interpolates binned x with band = 0.6', () => {
@@ -121,7 +121,7 @@ describe('Mark: Point', () => {
     const props = point.encodeEntry(model);
 
     expect(props.x).toEqual({
-      signal: 'scale("x", 0.4 * datum["bin_maxbins_10_a"] + 0.6 * datum["bin_maxbins_10_a_end"])'
+      signal: "scale('x', 0.4 * datum['bin_maxbins_10_a'] + 0.6 * datum['bin_maxbins_10_a_end'])"
     });
   });
   it('interpolates x timeUnit with timeUnitBand = 0.5', () => {
@@ -139,7 +139,7 @@ describe('Mark: Point', () => {
     });
 
     const props = point.encodeEntry(model);
-    expect(props.x).toEqual({signal: 'scale("x", 0.5 * datum["year_a"] + 0.5 * datum["year_a_end"])'});
+    expect(props.x).toEqual({signal: "scale('x', 0.5 * datum['year_a'] + 0.5 * datum['year_a_end'])"});
   });
 
   it('interpolates nominal x on a band scale with band = 0.6', () => {
@@ -238,7 +238,7 @@ describe('Mark: Point', () => {
 
     it('should test for invalid values on y', () => {
       expect(props.y).toEqual([
-        {field: {group: 'height'}, test: '!isValid(datum["yield"]) || !isFinite(+datum["yield"])'},
+        {field: {group: 'height'}, test: "!isValid(datum['yield']) || !isFinite(+datum['yield'])"},
         {scale: Y, field: 'yield'}
       ]);
     });
diff --git a/test/compile/mark/text.test.ts b/test/compile/mark/text.test.ts
index 338b103183..3ab0b37827 100644
--- a/test/compile/mark/text.test.ts
+++ b/test/compile/mark/text.test.ts
@@ -149,7 +149,7 @@ describe('Mark: Text', () => {
     });
 
     it('should map to text without template', () => {
-      expect(props.text).toEqual({signal: `isValid(datum["Origin"]) ? datum["Origin"] : ""+datum["Origin"]`});
+      expect(props.text).toEqual({signal: `isValid(datum['Origin']) ? datum['Origin'] : ''+datum['Origin']`});
     });
   });
 
@@ -237,14 +237,14 @@ describe('Mark: Text', () => {
 
     it('should map text to expression', () => {
       expect(props.text).toEqual({
-        signal: `format(datum["mean_Acceleration"], "")`
+        signal: `format(datum['mean_Acceleration'], '')`
       });
     });
 
     it('should map color to fill', () => {
       expect(props.fill).toEqual([
         {
-          test: '!isValid(datum["mean_Acceleration"]) || !isFinite(+datum["mean_Acceleration"])',
+          test: "!isValid(datum['mean_Acceleration']) || !isFinite(+datum['mean_Acceleration'])",
           value: null
         },
         {
diff --git a/test/compile/scale/domain.test.ts b/test/compile/scale/domain.test.ts
index afc4973fa8..292a649740 100644
--- a/test/compile/scale/domain.test.ts
+++ b/test/compile/scale/domain.test.ts
@@ -665,8 +665,8 @@ describe('compile/scale', () => {
         const _domain = testParseDomainForChannel(model, 'y');
 
         expect(_domain).toEqual([
-          {signal: `{data: datetime("Jan 1, 2007")}`},
-          {signal: `{data: datetime("Jan 1, 2009")}`}
+          {signal: `{data: datetime('Jan 1, 2007')}`},
+          {signal: `{data: datetime('Jan 1, 2009')}`}
         ]);
       });
 
@@ -685,8 +685,8 @@ describe('compile/scale', () => {
         const _domain = testParseDomainForChannel(model, 'y');
 
         expect(_domain).toEqual([
-          {signal: `{data: datetime("Jan 1, 2007")}`},
-          {signal: `{data: datetime("Jan 1, 2009")}`}
+          {signal: `{data: datetime('Jan 1, 2007')}`},
+          {signal: `{data: datetime('Jan 1, 2009')}`}
         ]);
       });
 
diff --git a/test/compile/signal.test.ts b/test/compile/signal.test.ts
index 315398a0ec..f4d266924a 100644
--- a/test/compile/signal.test.ts
+++ b/test/compile/signal.test.ts
@@ -11,7 +11,7 @@ describe('SignalRefWrapper', () => {
   });
 
   it('should serialize correctly', () => {
-    expect(stringify(s)).toBe('{"signal":"hello world"}');
+    expect(stringify(s)).toBe("{'signal':'hello world'}");
   });
 
   it('should look like a signal', () => {
diff --git a/test/timeunit.test.ts b/test/timeunit.test.ts
index 80e028bed8..20244b52a5 100644
--- a/test/timeunit.test.ts
+++ b/test/timeunit.test.ts
@@ -49,73 +49,73 @@ describe('timeUnit', () => {
   describe('fieldExpr', () => {
     it('should return correct field expression for yearmonthdatehoursminutesseconds', () => {
       expect(fieldExpr('yearmonthdatehoursminutesseconds', 'x')).toBe(
-        'datetime(year(datum["x"]), month(datum["x"]), date(datum["x"]), hours(datum["x"]), minutes(datum["x"]), seconds(datum["x"]), 0)'
+        "datetime(year(datum['x']), month(datum['x']), date(datum['x']), hours(datum['x']), minutes(datum['x']), seconds(datum['x']), 0)"
       );
     });
 
     it('should return correct field expression for quarter', () => {
-      expect(fieldExpr('quarter', 'x')).toBe('datetime(2012, (quarter(datum["x"])-1)*3, 1, 0, 0, 0, 0)');
+      expect(fieldExpr('quarter', 'x')).toBe("datetime(2012, (quarter(datum['x'])-1)*3, 1, 0, 0, 0, 0)");
     });
 
     it('should return correct field expression for day', () => {
-      expect(fieldExpr('day', 'x')).toBe('datetime(2012, 0, day(datum["x"])+1, 0, 0, 0, 0)');
+      expect(fieldExpr('day', 'x')).toBe("datetime(2012, 0, day(datum['x'])+1, 0, 0, 0, 0)");
     });
 
     it('should return correct field expression for milliseconds', () => {
-      expect(fieldExpr('milliseconds', 'x')).toBe('datetime(2012, 0, 1, 0, 0, 0, milliseconds(datum["x"]))');
+      expect(fieldExpr('milliseconds', 'x')).toBe("datetime(2012, 0, 1, 0, 0, 0, milliseconds(datum['x']))");
     });
 
     it('should return correct field expression for monthdate', () => {
-      expect(fieldExpr('monthdate', 'x')).toBe('datetime(2012, month(datum["x"]), date(datum["x"]), 0, 0, 0, 0)');
+      expect(fieldExpr('monthdate', 'x')).toBe("datetime(2012, month(datum['x']), date(datum['x']), 0, 0, 0, 0)");
     });
 
     it('should return correct field expression with utc for milliseconds', () => {
-      expect(fieldExpr('utcquarter', 'x')).toBe('datetime(2012, (utcquarter(datum["x"])-1)*3, 1, 0, 0, 0, 0)');
+      expect(fieldExpr('utcquarter', 'x')).toBe("datetime(2012, (utcquarter(datum['x'])-1)*3, 1, 0, 0, 0, 0)");
 
-      expect(fieldExpr('utcmilliseconds', 'x')).toBe('datetime(2012, 0, 1, 0, 0, 0, utcmilliseconds(datum["x"]))');
+      expect(fieldExpr('utcmilliseconds', 'x')).toBe("datetime(2012, 0, 1, 0, 0, 0, utcmilliseconds(datum['x']))");
     });
   });
 
   describe('template', () => {
     it('should return correct template for yearmonthdatehoursminutesseconds', () => {
       expect(formatExpression('yearmonthdatehoursminutesseconds', 'datum.x', false)).toBe(
-        'timeFormat(datum.x, timeUnitSpecifier(["year","month","date","hours","minutes","seconds"], {"year-month":"%b %Y ","year-month-date":"%b %d, %Y "}))'
+        "timeFormat(datum.x, timeUnitSpecifier(['year','month','date','hours','minutes','seconds'], {'year-month':'%b %Y ','year-month-date':'%b %d, %Y '}))"
       );
     });
 
     it('should return correct template for yearmonth (No comma)', () => {
       expect(formatExpression('yearmonth', 'datum.x', false)).toBe(
-        'timeFormat(datum.x, timeUnitSpecifier(["year","month"], {"year-month":"%b %Y ","year-month-date":"%b %d, %Y "}))'
+        "timeFormat(datum.x, timeUnitSpecifier(['year','month'], {'year-month':'%b %Y ','year-month-date':'%b %d, %Y '}))"
       );
     });
 
     it('should return correct template for day', () => {
       expect(formatExpression('day', 'datum.x', false)).toBe(
-        'timeFormat(datum.x, timeUnitSpecifier(["day"], {"year-month":"%b %Y ","year-month-date":"%b %d, %Y "}))'
+        "timeFormat(datum.x, timeUnitSpecifier(['day'], {'year-month':'%b %Y ','year-month-date':'%b %d, %Y '}))"
       );
     });
 
     it('should return correct template for day (shortened)', () => {
       expect(formatExpression('day', 'datum.x', false)).toBe(
-        'timeFormat(datum.x, timeUnitSpecifier(["day"], {"year-month":"%b %Y ","year-month-date":"%b %d, %Y "}))'
+        "timeFormat(datum.x, timeUnitSpecifier(['day'], {'year-month':'%b %Y ','year-month-date':'%b %d, %Y '}))"
       );
     });
 
     it('should return correct template for QUARTER', () => {
       expect(formatExpression('quarter', 'datum.x', false)).toBe(
-        'timeFormat(datum.x, timeUnitSpecifier(["quarter"], {"year-month":"%b %Y ","year-month-date":"%b %d, %Y "}))'
+        "timeFormat(datum.x, timeUnitSpecifier(['quarter'], {'year-month':'%b %Y ','year-month-date':'%b %d, %Y '}))"
       );
     });
 
     it('should return correct template for yearquarter', () => {
       expect(formatExpression('yearquarter', 'datum.x', false)).toBe(
-        'timeFormat(datum.x, timeUnitSpecifier(["year","quarter"], {"year-month":"%b %Y ","year-month-date":"%b %d, %Y "}))'
+        "timeFormat(datum.x, timeUnitSpecifier(['year','quarter'], {'year-month':'%b %Y ','year-month-date':'%b %d, %Y '}))"
       );
     });
 
     it('should return correct template for milliseconds', () => {
       expect(formatExpression('milliseconds', 'datum.x', false)).toBe(
-        'timeFormat(datum.x, timeUnitSpecifier(["milliseconds"], {"year-month":"%b %Y ","year-month-date":"%b %d, %Y "}))'
+        "timeFormat(datum.x, timeUnitSpecifier(['milliseconds'], {'year-month':'%b %Y ','year-month-date':'%b %d, %Y '}))"
       );
     });
 
@@ -125,13 +125,13 @@ describe('timeUnit', () => {
 
     it('should return correct template for yearmonth (No comma) with utc scale', () => {
       expect(formatExpression('yearmonth', 'datum.x', true)).toBe(
-        'utcFormat(datum.x, timeUnitSpecifier(["year","month"], {"year-month":"%b %Y ","year-month-date":"%b %d, %Y "}))'
+        "utcFormat(datum.x, timeUnitSpecifier(['year','month'], {'year-month':'%b %Y ','year-month-date':'%b %d, %Y '}))"
       );
     });
 
     it('should return correct template for utcyearmonth (No comma)', () => {
       expect(formatExpression('utcyearmonth', 'datum.x', true)).toBe(
-        'utcFormat(datum.x, timeUnitSpecifier(["year","month"], {"year-month":"%b %Y ","year-month-date":"%b %d, %Y "}))'
+        "utcFormat(datum.x, timeUnitSpecifier(['year','month'], {'year-month':'%b %Y ','year-month-date':'%b %d, %Y '}))"
       );
     });
   });
diff --git a/test/util.test.ts b/test/util.test.ts
index 852bc39bc6..65a761d259 100644
--- a/test/util.test.ts
+++ b/test/util.test.ts
@@ -45,11 +45,11 @@ describe('util', () => {
     });
 
     it('stringifies strings', () => {
-      expect(stringify('foo')).toBe('"foo"');
+      expect(stringify('foo')).toBe("'foo'");
     });
 
     it('stringifies objects', () => {
-      expect(stringify({foo: 42})).toBe('{"foo":42}');
+      expect(stringify({foo: 42})).toBe("{'foo':42}");
     });
   });
 
@@ -67,7 +67,7 @@ describe('util', () => {
     });
 
     it('hashes objects', () => {
-      expect(hash({foo: 42})).toBe('{"foo":42}');
+      expect(hash({foo: 42})).toBe("{'foo':42}");
     });
   });
 
@@ -142,19 +142,19 @@ describe('util', () => {
 
   describe('flatAccessWithDatum', () => {
     it('should parse foo.bar', () => {
-      expect(flatAccessWithDatum('foo.bar')).toBe('datum["foo.bar"]');
+      expect(flatAccessWithDatum('foo.bar')).toBe("datum['foo.bar']");
     });
 
     it('should return string value of field name', () => {
-      expect(flatAccessWithDatum('foo["bar"].baz')).toBe('datum["foo.bar.baz"]');
+      expect(flatAccessWithDatum('foo["bar"].baz')).toBe("datum['foo.bar.baz']");
     });
 
     it('should support custom datum', () => {
-      expect(flatAccessWithDatum('foo', 'parent')).toBe('parent["foo"]');
+      expect(flatAccessWithDatum('foo', 'parent')).toBe("parent['foo']");
     });
 
     it('should support escaped brackets', () => {
-      expect(flatAccessWithDatum('y\\[foo\\]')).toBe('datum["y[foo]"]');
+      expect(flatAccessWithDatum('y\\[foo\\]')).toBe("datum['y[foo]']");
     });
   });
 

From ccfafffaaa85338bd1205a1ed38679d60d5a99b5 Mon Sep 17 00:00:00 2001
From: liminge <liminge@andrew.cmu.edu>
Date: Sun, 18 Feb 2024 01:07:06 -0500
Subject: [PATCH 4/4] Is this modification aligned with the expectation?

---
 test/compile/mark/encoding/aria.test.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/test/compile/mark/encoding/aria.test.ts b/test/compile/mark/encoding/aria.test.ts
index a26aaa3c3a..aaf1a803f8 100644
--- a/test/compile/mark/encoding/aria.test.ts
+++ b/test/compile/mark/encoding/aria.test.ts
@@ -23,7 +23,7 @@ describe('compile/mark/encoding/aria', () => {
     expect(ariaMixins).toEqual({
       description: {
         signal:
-          '"category: " + (isValid(datum["category"]) ? datum["category"] : ""+datum["category"]) + "; value: " + (format(datum["value"], ""))'
+          "\"category: \" + (isValid(datum['category']) ? datum['category'] : \"\"+datum['category']) + \"; value: \" + (format(datum['value'], \"\"))"
       },
       ariaRoleDescription: {
         value: 'bar'
@@ -125,7 +125,7 @@ describe('compile/mark/encoding/aria', () => {
         value: 'mark'
       },
       description: {
-        signal: '"category: " + (isValid(datum["category"]) ? datum["category"] : ""+datum["category"])'
+        signal: "\"category: \" + (isValid(datum['category']) ? datum['category'] : \"\"+datum['category'])"
       }
     });
   });