fix(common): flat eq now returns false instead of comparing tostring …

…to prevent false positives
rimbu-org · Jul 3, 2021 · b045177 · b045177
1 parent 339cbea
commit b045177
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Showing 3 changed files with 21 additions and 10 deletions.
diff --git a/deno_dist/common/eq.ts b/deno_dist/common/eq.ts
@@ -203,7 +203,8 @@ export namespace Eq {
             return _objectEq(v1, v2);
           }
 
-          return _anyToStringEq(v1, v2);
+          // cannot establish that they are equal in flat mode
+          return false;
         }
       }
     };
@@ -213,7 +214,7 @@ export namespace Eq {
 
   /**
    * Returns an Eq instance that checks equality of any values. For composed values (objects and iterables)
-   * it will compare the JSON.stringify results of the values.
+   * it will compare with Object.is.
    * @typeparam T - the value type
    * @example
    * const eq = anyFlatEq()
@@ -229,7 +230,7 @@ export namespace Eq {
   /**
    * Returns an Eq instance that checks equality of any values. For composed values (objects and iterables)
    * it will enter 1 level, and if again compound values are found, they are compared
-   * using JSON.stringify.
+   * with Object.is.
    * @typeparam T - the value type
    * @example
    * const eq = anyFlatEq()

diff --git a/packages/common/src/eq.ts b/packages/common/src/eq.ts
@@ -203,7 +203,8 @@ export namespace Eq {
             return _objectEq(v1, v2);
           }
 
-          return _anyToStringEq(v1, v2);
+          // cannot establish that they are equal in flat mode
+          return false;
         }
       }
     };
@@ -213,7 +214,7 @@ export namespace Eq {
 
   /**
    * Returns an Eq instance that checks equality of any values. For composed values (objects and iterables)
-   * it will compare the JSON.stringify results of the values.
+   * it will compare with Object.is.
    * @typeparam T - the value type
    * @example
    * const eq = anyFlatEq()
@@ -229,7 +230,7 @@ export namespace Eq {
   /**
    * Returns an Eq instance that checks equality of any values. For composed values (objects and iterables)
    * it will enter 1 level, and if again compound values are found, they are compared
-   * using JSON.stringify.
+   * with Object.is.
    * @typeparam T - the value type
    * @example
    * const eq = anyFlatEq()

diff --git a/packages/common/test/eq.test.ts b/packages/common/test/eq.test.ts
@@ -59,16 +59,17 @@ describe('Eq', () => {
     ).toBe(false);
     expect(e(Object.is, Object.is)).toBe(true);
     expect(e({}, new (class Object {})())).toBe(false);
-    expect(e({}, {})).toBe(true);
+    // flat does not compare object contents, to be safe returns false
+    expect(e({}, {})).toBe(false);
     // not same constructor
     expect(e(new (class Object {})(), new (class Object {})())).toBe(false);
 
     class O {
       constructor(readonly v: number) {}
     }
 
-    // same constructor
-    expect(e(new O(1), new O(1))).toBe(true);
+    // same constructor but flat does not compare contents
+    expect(e(new O(1), new O(1))).toBe(false);
     // because toString gives [object object], this will be true
     // expect(e(new O(1), new O(2))).toBe(false);
   });
@@ -82,14 +83,22 @@ describe('Eq', () => {
     expect(e([1], [1, 3])).toBe(false);
     expect(e({}, { a: 1 })).toBe(false);
     expect(e({ a: 1 }, { a: 1 })).toBe(true);
-    expect(e({ a: 1, b: { c: 4 } }, { a: 1, b: { c: 4 } })).toBe(true);
+    // shallow only checks one level deep, to be safe will return false for deeper nested objects
+    expect(e({ a: 1, b: { c: 4 } }, { a: 1, b: { c: 4 } })).toBe(false);
     expect(e({ a: 1, b: { c: 4 } }, { a: 1, b: { c: 5 } })).toBe(false);
     expect(e(1, 2)).toBe(false);
     expect(e(2, 2)).toBe(true);
     expect(e(undefined, undefined)).toBe(true);
     expect(e('a', 'a')).toBe(true);
     expect(e('a', 'b')).toBe(false);
     expect(e(Symbol('a'), Symbol('a'))).toBe(false);
+
+    class O {
+      constructor(readonly v: number) {}
+    }
+
+    // same constructor
+    expect(e(new O(1), new O(1))).toBe(true);
   });
 
   it('anyDeepEq', () => {