feat(compiler): support for singleline, multiline & jsdoc comments (#22715)

PR Close #22715

packages/compiler/test/output/ts_emitter_spec.ts

@@ -414,10 +414,38 @@ const externalModuleIdentifier = new o.ExternalReference(anotherModuleUrl, 'some
           .toEqual('var a:{[key: string]:number} = (null as any);');
     });
 
-    it('should support a preamble', () => {
-      expect(emitStmt(o.variable('a').toStmt(), '/* SomePreamble */')).toBe([
-        '/* SomePreamble */', 'a;'
-      ].join('\n'));
+    describe('comments', () => {
+      it('should support a preamble', () => {
+        expect(emitStmt(o.variable('a').toStmt(), '/* SomePreamble */')).toBe([
+          '/* SomePreamble */', 'a;'
+        ].join('\n'));
+      });
+
+      it('should support singleline comments', () => {
+        expect(emitStmt(new o.CommentStmt('Simple comment'))).toBe('// Simple comment');
+      });
+
+      it('should support multiline comments', () => {
+        expect(emitStmt(new o.CommentStmt('Multiline comment', true)))
+            .toBe('/* Multiline comment */');
+        expect(emitStmt(new o.CommentStmt(`Multiline\ncomment`, true)))
+            .toBe(`/* Multiline\ncomment */`);
+      });
+
+      it('should support JSDoc comments', () => {
+        expect(emitStmt(new o.JSDocCommentStmt([{text: 'Intro comment'}])))
+            .toBe(`/**\n * Intro comment\n */`);
+        expect(emitStmt(new o.JSDocCommentStmt([
+          {tagName: o.JSDocTagName.Desc, text: 'description'}
+        ]))).toBe(`/**\n * @desc description\n */`);
+        expect(emitStmt(new o.JSDocCommentStmt([
+          {text: 'Intro comment'},
+          {tagName: o.JSDocTagName.Desc, text: 'description'},
+          {tagName: o.JSDocTagName.Id, text: '{number} identifier 123'},
+        ])))
+            .toBe(
+                `/**\n * Intro comment\n * @desc description\n * @id {number} identifier 123\n */`);
+      });
     });
 
     describe('emitter context', () => {
@@ -461,4 +489,4 @@ function calculateLineCol(text: string, offset: number): {line: number, col: num
     cur = next;
   }
   return {line, col: 0};
-}
+}