跟着Vam一起学习Typescript（第一期）

一、安装环境与配置
1、命令行安装

npm i -g typescript

2、快捷打开Vs Code编辑器

创建一个项目文件夹，在该文件夹下打开命令行工具，使用code .命令快速打开编辑器（如果计算机提示没有这个命令，请查找到编辑器安装目录bin文件夹下，复制地址。到系统的环境变量下Path，编辑，在前面加上;，粘贴进去就好了）。
3、运行typesript以及同步typesript与js转换

我们在项目文件夹下创建一个名叫demo1.ts文件。这就是我们学习typesript的起点，要记住typesript需要转换成js文件才可以被浏览器识别，所以需要运行命令：

tsc demo1.ts

这样就会在文件夹下生成一个名叫demo1.js文件。是不是感觉每次写完都要运行命令很烦，所以我们推荐使用Vs code编辑器，让你每次编写ts的时候都会同步编译成js文件。教程如下：
在项目文件夹下运行命令：

tsc --init

项目文件夹下，会生成一个tsconfig.json文件。取消注释 “outDir”: “./js”,，这就是输出js文件所要存放的地址，这里我改写了在项目文件夹下的js文件夹。

{
“compilerOptions”: {
/* Basic Options /
// “incremental”: true, / Enable incremental compilation /
“target”: “es5”, / Specify ECMAScript target version: ‘ES3’ (default), ‘ES5’, ‘ES2015’, ‘ES2016’, ‘ES2017’, ‘ES2018’, ‘ES2019’, ‘ES2020’, or ‘ESNEXT’. /
“module”: “commonjs”, / Specify module code generation: ‘none’, ‘commonjs’, ‘amd’, ‘system’, ‘umd’, ‘es2015’, ‘es2020’, 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”: “./js”, / 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 /
// “tsBuildInfoFile”: “./”, / Specify file to store incremental compilation information /
// “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. */
// "strictBindCallApply": true,           /* Enable strict 'bind', 'call', and 'apply' methods on functions. */
// "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. */
// "allowUmdGlobalAccess": true,          /* Allow accessing UMD globals from modules. */

/* 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. */

/* Advanced Options */
"forceConsistentCasingInFileNames": true  /* Disallow inconsistently-cased references to the same file. */

更多内容请见原文，原文转载自：https://blog.csdn.net/weixin_44519496/article/details/119945555