[Angular] ぼくのかんがえたさいきょうのsystem.jsのこんふぃぐふぁいる

ひさびさの投稿

# 背景
``Angular``で実装するときにつかう``SystemJS``の設定ファイルだけ``coffee-script``で記述していたのを、
``4.x``がリリースされたのを機に``Typescript``で書き直しました。
（``coffee``のほうが楽だったからサボっていただけですね。。）

***

# 環境
```shell-session
$ node -v
v7.9.0

$ npm -v
4.6.1

$ tsc -v
Version 2.3.2
```

***

# 各種ファイル

## package.json

```json:package.json
{
  "name": "heroes",
  "version": "1.0.0",
  "description": "This is Heroes App.",
  "scripts": {
    "p:client:w": "pug src -o assets --doctype html --pretty --watch",
    "s:client:w": "node-sass src -o assets --outstyle expanded --watch",
    "t:client:w": "tsc -p tsconfig-client.json --watch",
    "t:server:w": "tsc -p tsconfig-server.json --watch",
    "p:client": "pug src -o assets --doctype html",
    "s:client": "node-sass src -o assets --outstyle compressed",
    "t:client": "tsc -p tsconfig-client.json",
    "t:server": "tsc -p tsconfig-server.json",
    "build:cliend": "npm run p:client && npm run s:client && npm run t:client"
  },
  "author": "hoge hogeo <hoge.hogeo@example.com>",
  "license": "MIT",
  "dependencies": {
    "@angular/animations": "^4.1.3",
    "@angular/common": "^4.1.3",
    "@angular/compiler": "^4.1.3",
    "@angular/core": "^4.1.3",
    "@angular/forms": "^4.1.3",
    "@angular/http": "^4.1.3",
    "@angular/platform-browser": "^4.1.3",
    "@angular/platform-browser-dynamic": "^4.1.3",
    "@angular/router": "^4.1.3",
    "bootstrap": "^3.3.7",
    "font-awesome": "^4.7.0",
    "jquery": "^3.2.1",
    "reflect-metadata": "^0.1.10",
    "rxjs": "^5.4.0",
    "systemjs": "^0.20.12",
    "zone.js": "^0.8.11"
  },
  "devDependencies": {
    "@types/bootstrap": "^3.3.33",
    "@types/jquery": "^2.0.45"
  }
}
```

## tsconfig-client.json

```json:tsconfig-client.json
{
  "compilerOptions": {
    /* Basic Options */                       
    "target": "es5",                          /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', or 'ESNEXT'. */
    "module": "system",                       /* Specify module code generation: 'commonjs', 'amd', 'system', 'umd' or 'es2015'. */
    "lib": ["es2015", "dom"],                 /* Specify library files to be included in the compilation:  */
    // "allowJs": true,                       /* Allow javascript files to be compiled. */
    // "checkJs": true,                       /* Report errors in .js files. */
    // "jsx": "preserve",                     /* Specify JSX code generation: 'preserve', 'react-native', or 'react'. */
    // "declaration": true,                   /* Generates corresponding '.d.ts' file. */
    "sourceMap": true,                        /* Generates corresponding '.map' file. */
    // "outFile": "./",                       /* Concatenate and emit output to single file. */
    "outDir": "assets/scripts",               /* Redirect output structure to the directory. */
    "rootDir": "src/scripts",                 /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */
    "removeComments": true,                   /* Do not emit comments to output. */
    // "noEmit": true,                        /* Do not emit outputs. */
    // "importHelpers": true,                 /* Import emit helpers from 'tslib'. */
    // "downlevelIteration": true,            /* Provide full support for iterables in 'for-of', spread, and destructuring when targeting 'ES5' or 'ES3'. */
    // "isolatedModules": true,               /* Transpile each file as a separate module (similar to 'ts.transpileModule'). */
                                              
    /* Strict Type-Checking Options */        
    "strict": true,                           /* Enable all strict type-checking options. */
    // "noImplicitAny": true,                 /* Raise error on expressions and declarations with an implied 'any' type. */
    // "strictNullChecks": true,              /* Enable strict null checks. */
    /// "noImplicitThis": true,               /* Raise error on 'this' expressions with an implied 'any' type. */
    /// "alwaysStrict": true,                 /* Parse in strict mode and emit "use strict" for each source file. */
                                              
    /* Additional Checks */                   
    // "noUnusedLocals": true,                /* Report errors on unused locals. */
    // "noUnusedParameters": true,            /* Report errors on unused parameters. */
    // "noImplicitReturns": true,             /* Report error when not all code paths in function return a value. */
    // "noFallthroughCasesInSwitch": true,    /* Report errors for fallthrough cases in switch statement. */
                                              
    /* Module Resolution Options */           
    "moduleResolution": "node",               /* Specify module resolution strategy: 'node' (Node.js) or 'classic' (TypeScript pre-1.6). */
    // "baseUrl": "./",                       /* Base directory to resolve non-absolute module names. */
    // "paths": {},                           /* A series of entries which re-map imports to lookup locations relative to the 'baseUrl'. */
    // "rootDirs": [],                        /* List of root folders whose combined content represents the structure of the project at runtime. */
    // "typeRoots": [],                       /* List of folders to include type definitions from. */
    // "types": [],                           /* Type declaration files to be included in compilation. */
    // "allowSyntheticDefaultImports": true,  /* Allow default imports from modules with no default export. This does not affect code emit, just typechecking. */
                                              
    /* Source Map Options */                  
    // "sourceRoot": "./",                    /* Specify the location where debugger should locate TypeScript files instead of source locations. */
    // "mapRoot": "./",                       /* Specify the location where debugger should locate map files instead of generated locations. */
    // "inlineSourceMap": true,               /* Emit a single file with source maps instead of having a separate file. */
    // "inlineSources": true,                 /* Emit the source alongside the sourcemaps within a single file; requires '--inlineSourceMap' or '--sourceMap' to be set. */
                                              
    /* Experimental Options */                
    "experimentalDecorators": true,           /* Enables experimental support for ES7 decorators. */
    "emitDecoratorMetadata": true             /* Enables experimental support for emitting type metadata for decorators. */
  },
  "files": [
    "src/scripts/bootstrap/my-app.ts",
    "src/scripts/config/system.config.ts"
  ]
}
```

# 実装

## system.config.ts

```ts:system.config.ts
declare var System: any;

let run = (bootstrap: string) => {
  const APP_ROOT  = "assets/scripts";
  const BOOTSTRAP = "bootstrap/" + bootstrap + ".js";

  let angularPrefix: string = "@angular";

  let angularMaps: any = {};

  let angularModules: string[] = [
    "animations",
    "animations/browser",
    "common",
    "compiler",
    "core",
    "forms",
    "http",
    "platform-browser",
    "platform-browser-dynamic",
    "platform-browser/animations",
    "router",
  ];

  let systemPaths: {[key: string]: string} = {
    "npm:" : "node_modules/",
  };

  let systemMaps: {[key: string]: string} = {
    [APP_ROOT]  : APP_ROOT,

    // 3rd Party Libraries
    "rxjs"      : "npm:rxjs",
    "bootstrap" : "npm:bootstrap/dist/js/bootstrap.min.js",
    "jquery"    : "npm:jquery/dist/jquery.min.js",
  };

  let packages: {[key: string]: any} = {
    [APP_ROOT] : { defaultExtension : "js" },
    "rxjs"     : { defaultExtension : "js" },
  };

  angularModules.forEach((module: string) => {
    let _items: string[] = module.split("/");
    Object.assign(angularMaps, {
      [`${angularPrefix}/${module}`] : `${systemPaths["npm:"]}${angularPrefix}/${_items[0]}/bundles/${_items.join("-")}.umd.js`
    });
  });

  Object.assign(systemMaps, angularMaps);
  Object.assign(packages[APP_ROOT], { main : BOOTSTRAP });

  System.config({
    paths    : systemPaths,
    map      : systemMaps,
    packages : packages,
  });

  System.import(APP_ROOT).then(null, console.error.bind(console));
}
```

## my-app.ts

```ts:src/scripts/bootstrap/my-app.ts
import {PRODUCTION} from "./env";
import {enableProdMode} from "@angular/core";
if (PRODUCTION) { enableProdMode(); }
import "jquery";
import "bootstrap";
import {platformBrowserDynamic} from "@angular/platform-browser-dynamic";
import {HeroAppModule} from "../app/hero-app.module";
platformBrowserDynamic().bootstrapModule(HeroAppModule);
```




# 読み込み
```html:index.html
<!doctype html>
<html lang="ja">
<head>
<base href="/">
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width,initial-scale=1">
<title>Heroes</title>
<link rel="shortcut icon" href="assets/images/favicon.ico" type="image/vnd.microsoft.icon">
<link rel="stylesheet" href="node_modules/bootstrap/dist/css/bootstrap.min.css">
<link rel="stylesheet" href="node_modules/font-awesome/css/font-awesome.min.css">
<body>
<my-app>Loading ...</my-app>
<script src="node_modules/zone.js/dist/zone.js"></script>
<script src="node_modules/reflect-metadata/Reflect.js"></script>
<script src="node_modules/systemjs/dist/system.js"></script>
<script src="assets/scripts/config/system.config.js"></script>
<script>run("my-app");</script>
```


# あとがき

``run()``をグローバル変数にしている理由は、
最初に読み込むHTMLをPHPから動的に生成し、
アプリケーションを切り替えられるようにするためです。

ですので
単一アプリケーションや、グローバル汚染が気になる場合は

```ts
let run = (bootstrap: string) => {
  // ...
}
```

を

```ts
((bootstrap: string) => {
  // ...
})("my-app");
```

としてあげればいいと思います。