第一篇：使用Typescript开发Nodejs
这是实现IoC系列的第一步，因为是基于TypeScript的，所以首先我们来看一下如何使用TypeScript来开发NodeJs项目
TypeScript已经得到广泛的应用，一般开发Nodejs后端时都会使用成熟的框架，比如Nestjs，但是一些小工具，就没有必要使用框架了，但是又想使用typescript开发，网上有很多关于使用typescript来开发Nodejs应用的教程，我这里做下记录，可能的话会写给npm包，一条命令生成应用的骨架。
一. npm init: 生成应用骨架
npm init
会在当前目录下生成package.json文件
二. 安装typescript
npm install typescript --save
三.初始化typescript环境
.\node_modules\.bin\tsc --init
生成默认的tsconfig.json文件
四.修改默认的tsconfig.json文件
- 项目中会使用到一些es6的语法，比如Symbol，所以需要在tsconfig.json的lib中添加ES2015
- 项目中会使用到console等命令，使用需要在lib中添加dom
- 默认的tsc编译文件的输出是当前路径，我们修改为dist
- Debug时需要用到sourcemap,打开sourcemap
- 项目中还会使用到装饰器和反射的metadata这个实验性技术，所以需要打开experimentalDecorators和emitDecoratorMetadata
- 项目中使用的代码都是放在src下面，所以在与compilerOptions平级的地方加上include: ["src/**/*"]
1 {
2 "compilerOptions": {
3 /* Visit https://aka.ms/tsconfig.json to read more about this file */
4
5 /* Basic Options */
6 // "incremental": true, /* Enable incremental compilation */
7 "target": "es5", /* Specify ECMAScript target version: \'ES3\' (default), \'ES5\', \'ES2015\', \'ES2016\', \'ES2017\', \'ES2018\', \'ES2019\', \'ES2020\', or \'ESNEXT\'. */
8 "module": "commonjs", /* Specify module code generation: \'none\', \'commonjs\', \'amd\', \'system\', \'umd\', \'es2015\', \'es2020\', or \'ESNext\'. */
9 "lib": ["ES2015", "DOM"], /* Specify library files to be included in the compilation. */
10 // "allowJs": true, /* Allow javascript files to be compiled. */
11 // "checkJs": true, /* Report errors in .js files. */
12 // "jsx": "preserve", /* Specify JSX code generation: \'preserve\', \'react-native\', or \'react\'. */
13 // "declaration": true, /* Generates corresponding \'.d.ts\' file. */
14 // "declarationMap": true, /* Generates a sourcemap for each corresponding \'.d.ts\' file. */
15 "sourceMap": true, /* Generates corresponding \'.map\' file. */
16 // "outFile": "./", /* Concatenate and emit output to single file. */
17 "outDir": "dist", /* Redirect output structure to the directory. */
18 // "rootDir": "./", /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */
19 // "composite": true, /* Enable project compilation */
20 // "tsBuildInfoFile": "./", /* Specify file to store incremental compilation information */
21 // "removeComments": true, /* Do not emit comments to output. */
22 // "noEmit": true, /* Do not emit outputs. */
23 // "importHelpers": true, /* Import emit helpers from \'tslib\'. */
24 // "downlevelIteration": true, /* Provide full support for iterables in \'for-of\', spread, and destructuring when targeting \'ES5\' or \'ES3\'. */
25 // "isolatedModules": true, /* Transpile each file as a separate module (similar to \'ts.transpileModule\'). */
26
27 /* Strict Type-Checking Options */
28 "strict": true, /* Enable all strict type-checking options. */
29 // "noImplicitAny": true, /* Raise error on expressions and declarations with an implied \'any\' type. */
30 // "strictNullChecks": true, /* Enable strict null checks. */
31 // "strictFunctionTypes": true, /* Enable strict checking of function types. */
32 // "strictBindCallApply": true, /* Enable strict \'bind\', \'call\', and \'apply\' methods on functions. */
33 // "strictPropertyInitialization": true, /* Enable strict checking of property initialization in classes. */
34 // "noImplicitThis": true, /* Raise error on \'this\' expressions with an implied \'any\' type. */
35 // "alwaysStrict": true, /* Parse in strict mode and emit "use strict" for each source file. */
36
37 /* Additional Checks */
38 // "noUnusedLocals": true, /* Report errors on unused locals. */
39 // "noUnusedParameters": true, /* Report errors on unused parameters. */
40 // "noImplicitReturns": true, /* Report error when not all code paths in function return a value. */
41 // "noFallthroughCasesInSwitch": true, /* Report errors for fallthrough cases in switch statement. */
42 // "noUncheckedIndexedAccess": true, /* Include \'undefined\' in index signature results */
43
44 /* Module Resolution Options */
45 // "moduleResolution": "node", /* Specify module resolution strategy: \'node\' (Node.js) or \'classic\' (TypeScript pre-1.6). */
46 // "baseUrl": "./", /* Base directory to resolve non-absolute module names. */
47 // "paths": {}, /* A series of entries which re-map imports to lookup locations relative to the \'baseUrl\'. */
48 // "rootDirs": [], /* List of root folders whose combined content represents the structure of the project at runtime. */
49 // "typeRoots": [], /* List of folders to include type definitions from. */
50 // "types": [], /* Type declaration files to be included in compilation. */
51 // "allowSyntheticDefaultImports": true, /* Allow default imports from modules with no default export. This does not affect code emit, just typechecking. */
52 "esModuleInterop": true, /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies \'allowSyntheticDefaultImports\'. */
53 // "preserveSymlinks": true, /* Do not resolve the real path of symlinks. */
54 // "allowUmdGlobalAccess": true, /* Allow accessing UMD globals from modules. */
55
56 /* Source Map Options */
57 // "sourceRoot": "", /* Specify the location where debugger should locate TypeScript files instead of source locations. */
58 // "mapRoot": "", /* Specify the location where debugger should locate map files instead of generated locations. */
59 // "inlineSourceMap": true, /* Emit a single file with source maps instead of having a separate file. */
60 // "inlineSources": true, /* Emit the source alongside the sourcemaps within a single file; requires \'--inlineSourceMap\' or \'--sourceMap\' to be set. */
61
62 /* Experimental Options */
63 "experimentalDecorators": true, /* Enables experimental support for ES7 decorators. */
64 "emitDecoratorMetadata": true, /* Enables experimental support for emitting type metadata for decorators. */
65
66 /* Advanced Options */
67 "skipLibCheck": true, /* Skip type checking of declaration files. */
68 "forceConsistentCasingInFileNames": true /* Disallow inconsistently-cased references to the same file. */
69 },
70 "include": [
71 "src/**/*"
72 ]
73 }
tsconfig.json
五.修改package.json文件
1. 添加typescript编译命令 tsc --watch
2. 添加启动项目的命令 node dist/index.js
1 {
2 "name": "ts-ioc",
3 "version": "1.0.0",
4 "description": "this is a tool for project to use the IoC and DI",
5 "main": "index.js",
6 "scripts": {
7 "test": "echo \"Error: no test specified\" && exit 1",
8 "tsc": "tsc --watch",
9 "start": "node dist/index.js"
10 },
11 "author": "Jason",
12 "license": "ISC",
13 "dependencies": {
14 "typescript": "^4.1.3"
15 }
16 }
package.json
六.启动项目
1. 先在一个窗口中编译typescript
npm run-script tsc
2. 打开另外一个窗口，启动项目
npm start
至此，简单的使用typescript来开发nodejs就完成了，还有很多需要优化的地方，比如使用webpack把启动变成一步，还有debug的步骤。
七.热更新
之前启动项目需要npm run-script tsc && npm start,并且是没有热更新的，即修改完代码没有立即重新启动。
这里使用nodemon这个库，实现typescript代码的热更新。
nodemon -e ts --exec ts-node src/index.ts
这里用到了nodemon和ts-node,所以需要先安装它们
1 npm install nodemon --save-dev 2 npm install ts-node --save-dev
然后更新package.json文件
1 "scripts": {
2 "test": "echo \"Error: no test specified\" && exit 1",
3 "tsc": "tsc --watch",
4 "start": "nodemon -e ts --exec ts-node src/index.ts",
5 "webpack": "webpack --config webpack.config.js --watch"
6 },可以看到，使用了 nodemon -e ts --exec ts-node src/index.ts 来启动命令，-e ts表示这个是监听ts文件的，也可以写-e ts,tsx表示监听ts文件和tsc文件。
--exec表示需要使用ts-node来编译代码。
这样，就可以实现修改代码后自己重启了。
下一篇文章会实现一个简单的IoC container