Mangle exported symbols (microsoft#182935)

* Mangle exported functions

For microsoft#180461

This prototype tries to mangle exported functions, saving a further 440kb from the bundle size

* Fix missing call

* Also try mangling top level exported consts too

* Fixing errors

* Don't run on build files

* Skip a few more manglings and revert change to namespace

* Skip a few more monaco files

* Also mangle consts that shadow types

This increases savings up to 3325

* Also mangle exported classes

* Skip mangling more localization functions for now

* Opt out pfs

* Update build script

* Run find locations task in parallel

This should speed up compile

* Cleanup before close

* Limit workers to avoid hitting memory limit

* Limit pool size

* Skip one more mangling

* Exclude entrypoints from mangling

* Try to fix web build and clean up code

* Exempt a few more projects

* Exempt another file

* Also exempt html

* Skip mangling ext entrypoints

* Use prefix that can't be confused with rpc calls

* Fix max call stack error

* Switch prefixes

* Don't mangle ambient declarations

* Use correct way of checking modifier flags

* Workaround getCombinedModifierFlags not doing what I'd expect

Maybe needs the checker to be enabled too? Just check parent chain instead for now

* Clean up code and add logic showing how enum mangling could work

* Remove a few more skipMangles

Use entrypoints instead

* Fix entrypoint name

Author: mjbvz

build/lib/compilation.js

@@ -17,7 +17,7 @@ import * as os from 'os';
 import ts = require('typescript');
 import * as File from 'vinyl';
 import * as task from './task';
-import { Mangler } from './mangleTypeScript';
+import { Mangler } from './mangle/index';
 import { RawSourceMap } from 'source-map';
 const watch = require('./watch');
 
@@ -124,21 +124,22 @@ export function compileTask(src: string, out: string, build: boolean, options: {
 		// mangle: TypeScript to TypeScript
 		let mangleStream = es.through();
 		if (build && !options.disableMangle) {
-			let ts2tsMangler = new Mangler(compile.projectPath, (...data) => fancyLog(ansiColors.blue('[mangler]'), ...data));
+			let ts2tsMangler = new Mangler(compile.projectPath, (...data) => fancyLog(ansiColors.blue('[mangler]'), ...data), { mangleExports: true, manglePrivateFields: true });
 			const newContentsByFileName = ts2tsMangler.computeNewFileContents(new Set(['saveState']));
-			mangleStream = es.through(function write(data: File & { sourceMap?: RawSourceMap }) {
+			mangleStream = es.through(async function write(data: File & { sourceMap?: RawSourceMap }) {
 				type TypeScriptExt = typeof ts & { normalizePath(path: string): string };
 				const tsNormalPath = (<TypeScriptExt>ts).normalizePath(data.path);
-				const newContents = newContentsByFileName.get(tsNormalPath);
+				const newContents = (await newContentsByFileName).get(tsNormalPath);
 				if (newContents !== undefined) {
 					data.contents = Buffer.from(newContents.out);
 					data.sourceMap = newContents.sourceMap && JSON.parse(newContents.sourceMap);
 				}
 				this.push(data);
-			}, function end() {
-				this.push(null);
+			}, async function end() {
 				// free resources
-				newContentsByFileName.clear();
+				(await newContentsByFileName).clear();
+
+				this.push(null);
 				(<any>ts2tsMangler) = undefined;
 			});
 		}