angular-docs-cn/packages/compiler-cli

Angular Template Compiler

Angular applications are built with templates, which may be .html or .css files, or may be inline template attributes on Decorators like @Component.

These templates are compiled into executable JS at application runtime (except in interpretation mode). This compilation can occur on the client, but it results in slower bootstrap time, and also requires that the compiler be included in the code downloaded to the client.

You can produce smaller, faster applications by running Angular's compiler as a build step, and then downloading only the executable JS to the client.

Install and use

# First install angular, see https://github.com/angular/angular/blob/master/CHANGELOG.md#200-rc0-2016-05-02
$ npm install @angular/compiler-cli typescript@next @angular/platform-server @angular/compiler
# Optional sanity check, make sure TypeScript can compile.
$ ./node_modules/.bin/tsc -p path/to/project
# ngc is a drop-in replacement for tsc.
$ ./node_modules/.bin/ngc -p path/to/project

In order to write a bootstrap that imports the generated code, you should first write your top-level component, and run ngc once to produce a generated .ngfactory.ts file. Then you can add an import statement in the bootstrap allowing you to bootstrap off the generated code:

main.module.ts
-------------
import {BrowserModule} from '@angular/platform-browser';
import {Component, NgModule, ApplicationRef} from '@angular/core';

@Component(...)
export class MyComponent {}

@NgModule({
  imports: [BrowserModule],
  declarations: [MyComponent],
  entryComponents: [MyComponent]
})
export class MainModule {
  constructor(appRef: ApplicationRef) {
    appRef.bootstrap(MyComponent);
  }
}

bootstrap.ts
-------------

import {MainModuleNgFactory} from './main.module.ngfactory';
import {platformBrowser} from '@angular/platform-browser';

platformBrowser().bootstrapModuleFactory(MainModuleNgFactory);

Configuration

The tsconfig.json file may contain an additional configuration block:

 "angularCompilerOptions": {
   "genDir": ".",
   "debug": true
 }

genDir

the genDir option controls the path (relative to tsconfig.json) where the generated file tree will be written. If genDir is not set, then the code will be generated in the source tree, next to your original sources. More options may be added as we implement more features.

We recommend you avoid checking generated files into version control. This permits a state where the generated files in the repository were created from sources that were never checked in, making it impossible to reproduce the current state. Also, your changes will effectively appear twice in code reviews, with the generated version inscrutible by the reviewer.

In TypeScript 1.8, the generated sources will have to be written alongside your originals, so set genDir to the same location as your files (typicially the same as rootDir). Add **/*.ngfactory.ts and **/*.ngsummary.json to your .gitignore or other mechanism for your version control system.

In TypeScript 1.9 and above, you can add a generated folder into your application, such as codegen. Using the rootDirs option, you can allow relative imports like import {} from './foo.ngfactory' even though the src and codegen trees are distinct. Add **/codegen to your .gitignore or similar.

Note that in the second option, TypeScript will emit the code into two parallel directories as well. This is by design, see https://github.com/Microsoft/TypeScript/issues/8245. This makes the configuration of your runtime module loader more complex, so we don't recommend this option yet.

debug

Set the debug option to true to generate debug information in the generate files. Default to false.

See the example in the test/ directory for a working example.

Compiler CLI

This program mimics the TypeScript tsc command line. It accepts a -p flag which points to a tsconfig.json file, or a directory containing one.

This CLI is intended for demos, prototyping, or for users with simple build systems that run bare tsc.

Users with a build system should expect an Angular template plugin. Such a plugin would be based on the public_api.ts in this directory, but should share the TypeScript compiler instance with the one already used in the plugin for TypeScript typechecking and emit.

Design

At a high level, this program

• collects static metadata about the sources
• uses the OfflineCompiler from @angular/compiler to codegen additional .ts files
• these .ts files are written to the genDir path, then compiled together with the application.

For developers

# Build Angular and the compiler
./build.sh

# Run the test once
# (First edit the LINKABLE_PKGS to use npm link instead of npm install)
$ ./scripts/ci/offline_compiler_test.sh

# Keep a package fresh in watch mode
./node_modules/.bin/tsc -p packages/compiler/tsconfig-build.json -w

# Recompile @angular/core module (needs to use tsc-ext to keep the metadata)
$ export NODE_PATH=${NODE_PATH}:$(pwd)/dist/all:$(pwd)/dist/tools
$ node dist/tools/@angular/compiler-cli/src/main -p packages/core/tsconfig-build.json

# Iterate on the test
$ cd /tmp/wherever/e2e_test.1464388257/
$ ./node_modules/.bin/ngc
$ ./node_modules/.bin/jasmine test/*_spec.js