作者：amosworker
时间：2018/09/01
Typescript是微软开发的一个JavaScript的超级。著名前端框架的Angular和HTML5游戏引擎Egret等都选择了Typescript作为编写语言。“工欲善其事，必先利其器”，在学习Typescript语言之前必须要有一个良好的开发环境。这里笔者选择了轻量的Visual Studio Code，此工具具有轻量、跨平台、插件丰富等特点，是一款非常优秀的开发工具。
1、首先需要安装Nodejs，安装过程网上很容易搜到，在此不再介绍。安装完成后，在命令窗口输入
$ node -v
v8.11.4
2、安装typescript模块
$ npm install -g typescript
安装完成后，可以查看typescript模块的版本号
$ tsc -v
Version 3.0.3
3、创建项目目录，在命令窗口中进入该项目目录,创建tsconfig.json。例如项目地址是D:\test\ts。
$ D:
$ cd test\ts
$ tsc --init
在项目目录下会生成一个tsconfig.json文件
{
"compilerOptions": {
/* Basic Options */
"target": "es5", /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017','ES2018' or 'ESNEXT'. */
"module": "commonjs", /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */
// "lib": [], /* 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. */
// "declarationMap": true, /* Generates a sourcemap for each corresponding '.d.ts' file. */
// "sourceMap": true, /* Generates corresponding '.map' file. */
// "outFile": "./", /* Concatenate and emit output to single file. */
// "outDir": "./", /* Redirect output structure to the directory. */
// "rootDir": "./", /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */
// "composite": true, /* Enable project compilation */
// "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. */
// "strictFunctionTypes": true, /* Enable strict checking of function types. */
// "strictPropertyInitialization": true, /* Enable strict checking of property initialization in classes. */
// "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. */
"esModuleInterop": true /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
// "preserveSymlinks": true, /* Do not resolve the real path of symlinks. */
/* 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. */
}
}
里面有很多配置项，大家可以根据各自的需要来定制。本文用的示例配置如下,
{
"compilerOptions": {
"target": "es5",
"module": "commonjs'",
"outDir": "./js/",
"rootDir": "./tscript/",
"esModuleInterop": true
}
}
新建tscript、js文件夹，分别用作存放typescript、javascript文件。
4、测试编译
在Visual studio code中打开ts目录，在tscript目录中新建test.ts文件。
class Person {
hobby: string;
constructor(hobby: string) {
this.hobby = hobby;
}
echo() {
return '我就喜欢：' + this.hobby;
}
}
let person = new Person('看书，习武，书法，旅游');
let hobby = person.echo();
console.log(hobby);
然后点击菜单中的Tasks->Run Task。
之后会出现tsc:build 、tsc:watch两个选项
其中tsc:build选项是用于一次编译。tsc:watch选项可以监测ts文件的改动，可以进行实时编译，非常方便。经过编译后的文件会存放在之前配置好的js文件目录下。
"use strict";
var Person = /** @class */ (function () {
function Person(hobby) {
this.hobby = hobby;
}
Person.prototype.echo = function () {
return '我就喜欢：' + this.hobby;
};
return Person;
}());
var person = new Person('看书，习武，书法，旅游');
var hobby = person.echo();
console.log(hobby);
如此就可以进行Typescript之旅了。~~