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 }
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 }
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
