refactor(compiler-cli): remove tsickle from dependencies (#25649)

Users can still install tsickle if they want closure-compatible output.

PR Close #25649

packages/compiler-cli/package.json

@@ -12,7 +12,6 @@
   "dependencies": {
     "reflect-metadata": "^0.1.2",
     "minimist": "^1.2.0",
-    "tsickle": "^0.32.1",
     "chokidar": "^1.4.2",
     "convert-source-map": "^1.5.1",
     "magic-string": "^0.25.0",

packages/compiler-cli/src/main.ts

@@ -11,11 +11,8 @@
 import 'reflect-metadata';
 
 import * as ts from 'typescript';
-import * as fs from 'fs';
-import * as path from 'path';
 import * as tsickle from 'tsickle';
 import * as api from './transformers/api';
-import * as ngc from './transformers/entry_points';
 import {GENERATED_FILES} from './transformers/util';
 
 import {exitCodeFromResult, performCompilation, readConfiguration, formatDiagnostics, Diagnostics, ParsedConfiguration, PerformCompilationResult, filterErrorsAndWarnings} from './perform_compile';
@@ -66,6 +63,7 @@ function createEmitCallback(options: api.CompilerOptions): api.TsEmitCallback|un
     convertIndexImportShorthand: false, transformDecorators, transformTypesToClosure,
   };
 
+  if (options.annotateForClosureCompiler || options.annotationsAs === 'static fields') {
     return ({
              program,
              targetSourceFile,
@@ -76,12 +74,26 @@ function createEmitCallback(options: api.CompilerOptions): api.TsEmitCallback|un
              host,
              options
            }) =>
-             tsickle.emitWithTsickle(
-                 program, {...tsickleHost, options, host}, host, options, targetSourceFile,
-                 writeFile, cancellationToken, emitOnlyDtsFiles, {
+               // tslint:disable-next-line:no-require-imports only depend on tsickle if requested
+        require('tsickle').emitWithTsickle(
+            program, {...tsickleHost, options, host}, host, options, targetSourceFile, writeFile,
+            cancellationToken, emitOnlyDtsFiles, {
               beforeTs: customTransformers.before,
               afterTs: customTransformers.after,
             });
+  } else {
+    return ({
+             program,
+             targetSourceFile,
+             writeFile,
+             cancellationToken,
+             emitOnlyDtsFiles,
+             customTransformers = {},
+           }) =>
+               program.emit(
+                   targetSourceFile, writeFile, cancellationToken, emitOnlyDtsFiles,
+                   {after: customTransformers.after, before: customTransformers.before});
+  }
 }
 
 export interface NgcParsedConfiguration extends ParsedConfiguration { watch?: boolean; }

packages/compiler-cli/test/ngc_spec.ts

@@ -554,10 +554,10 @@ describe('ngc transformer command-line', () => {
     });
 
     describe('closure', () => {
-      it('should not generate closure specific code by default', () => {
+      it('should not run tsickle by default', () => {
         writeConfig(`{
           "extends": "./tsconfig-base.json",
-          "files": ["mymodule.ts"]
+          "files": ["mymodule.ts"],
         }`);
         write('mymodule.ts', `
         import {NgModule, Component} from '@angular/core';
@@ -575,7 +575,8 @@ describe('ngc transformer command-line', () => {
         const mymodulejs = path.resolve(outDir, 'mymodule.js');
         const mymoduleSource = fs.readFileSync(mymodulejs, 'utf8');
         expect(mymoduleSource).not.toContain('@fileoverview added by tsickle');
-        expect(mymoduleSource).toContain('MyComp.decorators = [');
+        expect(mymoduleSource).toContain('MyComp = __decorate');
+        expect(mymoduleSource).not.toContain('MyComp.decorators = [');
       });
 
       it('should add closure annotations', () => {