feat: Add support for comments in output (#80)

simenandre · May 23, 2021 · b1da522 · b1da522
1 parent 3393430
commit b1da522
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Showing 3 changed files with 95 additions and 1 deletion.
diff --git a/src/__tests__/main.test.ts b/src/__tests__/main.test.ts
@@ -625,4 +625,67 @@ describe('runtype generation', () => {
       "
     `);
   });
+
+  it('comments', () => {
+    const source = generateRuntypes(
+      {
+        name: 'Event',
+        comment: 'An event object',
+        type: {
+          kind: 'record',
+          fields: [
+            {
+              name: 'name',
+              type: { kind: 'string' },
+              comment: 'Single line comment',
+            },
+            {
+              name: 'age',
+              type: { kind: 'string' },
+              comment: 'Single line comment.\nWith newlines',
+            },
+            {
+              name: 'id',
+              type: { kind: 'string' },
+              comment: ['Multi line comment', 'As array'],
+            },
+            {
+              name: 'noComment1',
+              type: { kind: 'string' },
+              comment: [],
+            },
+            {
+              name: 'noComment2',
+              type: { kind: 'string' },
+              comment: '',
+            },
+          ],
+        },
+      },
+      { includeTypes: false },
+    );
+
+    expect(source).toMatchInlineSnapshot(`
+      "import * as rt from \\"runtypes\\";
+
+      // An event object
+      const event = rt.Record({
+        // Single line comment
+        name: rt.String
+        /**
+         * Single line comment.
+         * With newlines
+         */,
+        age: rt.String
+        /**
+         * Multi line comment
+         * As array
+         */,
+        id: rt.String,
+        noComment1: rt.String,
+        noComment2: rt.String,
+      });
+      "
+    `);
+  });
 });
diff --git a/src/main.ts b/src/main.ts
@@ -97,6 +97,9 @@ function writeRootType(
   const { formatRuntypeName, formatTypeName, includeTypes } = options;
   const runtypeName = formatRuntypeName(node.name);
   const typeName = formatTypeName(node.name);
+  if (node.comment) {
+    writeComment(w, node.comment);
+  }
   w.conditionalWrite(Boolean(node.export), 'export ');
   w.write(`const ${runtypeName}=`);
   writeAnyType(options, w, node.type);
@@ -219,6 +222,25 @@ function writeIntersectionType(
   w.write(')');
 }
 
+function writeComment(w: CodeWriter, comment: string | string[]) {
+  const lines = (Array.isArray(comment) ? comment : [comment])
+    .map((e) => e.trim())
+    .map((e) => e.split('\n'))
+    .reduce((prev, cur) => [...prev, ...cur], []);
+
+  if (lines.length === 0) {
+    return;
+  } else if (lines.length === 1) {
+    w.write(`// ${lines[0]}\n`);
+  } else {
+    w.write(`/**\n`);
+    for (const line of lines) {
+      w.write(`* ${line}\n`);
+    }
+    w.write(`*/\n`);
+  }
+}
+
 /**
  * public for testing
  *
@@ -273,6 +295,9 @@ function writeRecordType(
   for (const fieldKind of fieldKinds) {
     w.write('rt.Record({');
     for (const field of fieldKind.fields) {
+      if (field.comment) {
+        writeComment(w, field.comment);
+      }
       w.write(field.name);
       w.write(':');
       writeAnyType(options, w, field.type);

diff --git a/src/types.ts b/src/types.ts
@@ -50,6 +50,7 @@ export type RecordField = {
   type: AnyType;
   readonly?: boolean;
   nullable?: boolean;
+  comment?: string | string[];
 };
 
 export type RecordType = {
@@ -162,7 +163,12 @@ export type AnyType = rt.Static<typeof anyTypeRt>;
 
 export const rootTypeRt = rt.Intersect(
   rt.Record({ name: rt.String, type: anyTypeRt }),
-  rt.Record({ export: rt.Boolean }).asPartial(),
+  rt
+    .Record({
+      export: rt.Boolean,
+      comment: rt.Union(rt.String, rt.Array(rt.String)),
+    })
+    .asPartial(),
 );
 
 export type RootType = rt.Static<typeof rootTypeRt>;