前期准备

  1. #安装一些全局的npm包
  3. # 安装yarn包，用于管理安装npm包
  4. npm i yarn -g
  6. # 安装typescript包， 用于学习typescript
  7. npm i typescript -g
  9. # 安装ts-node包，用于直观了解运行typescript文件后的结果
  10. npm i ts-node -g

项目初始化

  1. #创建项目文件夹并进入
  2. mkdir ts-init && cd ts-init
  4. #yarn初始化项目， -y表示不需要确认，直接按默认的来
  5. yarn init -y
  7. #typescript初始化项目， 全局安装typescript包后，有个tsc命令
  8. tsc --init
  10. #安装typescript npm包到本地， 如果你全局安装过typescript，这一步可以略过
  11. yarn add typescript -D

package.json文件是yarn初始化创建的，这里script脚本是一些命令， 例如执行yarn dev它表示用ts-node命令运行index.ts文件，yarn build表示用tsc命令编译项目文件下的ts文件，yarn watch表示监听项目文件下ts文件的变化并做出编译。

  1. {
  2.   "name": "ts-init",
  3.   "version": "1.0.0",
  4.   "main": "index.js",
  5.   "license": "MIT",
  6.   "scripts": {
  7.     "dev": "ts-node index.js",
  8.     "build": "tsc",
  9.     "watch": "tsc -w"
  10.   },
  11.   "dependencies": {},
  12.   "devDependencies": {
  13.     "typescript": "^4.6.3"
  14.   }
  15. }

tsconfig.json这个文件是tsc初始化typescirpt项目所创建的文件，包含了一些配置信息

  1. {
  2.   "compilerOptions": {
  3.     /* Visit https://aka.ms/tsconfig.json to read more about this file */
  5.     /* Projects */
  6.     // "incremental": true,                              /* Enable incremental compilation */
  7.     // "composite": true,                                /* Enable constraints that allow a TypeScript project to be used with project references. */
  8.     // "tsBuildInfoFile": "./",                          /* Specify the folder for .tsbuildinfo incremental compilation files. */
  9.     // "disableSourceOfProjectReferenceRedirect": true,  /* Disable preferring source files instead of declaration files when referencing composite projects */
  10.     // "disableSolutionSearching": true,                 /* Opt a project out of multi-project reference checking when editing. */
  11.     // "disableReferencedProjectLoad": true,             /* Reduce the number of projects loaded automatically by TypeScript. */
  13.     /* Language and Environment */
  14.     "target": "es2016",                                  /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */
  15.     // "lib": [],                                        /* Specify a set of bundled library declaration files that describe the target runtime environment. */
  16.     // "jsx": "preserve",                                /* Specify what JSX code is generated. */
  17.     // "experimentalDecorators": true,                   /* Enable experimental support for TC39 stage 2 draft decorators. */
  18.     // "emitDecoratorMetadata": true,                    /* Emit design-type metadata for decorated declarations in source files. */
  19.     // "jsxFactory": "",                                 /* Specify the JSX factory function used when targeting React JSX emit, e.g. 'React.createElement' or 'h' */
  20.     // "jsxFragmentFactory": "",                         /* Specify the JSX Fragment reference used for fragments when targeting React JSX emit e.g. 'React.Fragment' or 'Fragment'. */
  21.     // "jsxImportSource": "",                            /* Specify module specifier used to import the JSX factory functions when using `jsx: react-jsx*`.` */
  22.     // "reactNamespace": "",                             /* Specify the object invoked for `createElement`. This only applies when targeting `react` JSX emit. */
  23.     // "noLib": true,                                    /* Disable including any library files, including the default lib.d.ts. */
  24.     // "useDefineForClassFields": true,                  /* Emit ECMAScript-standard-compliant class fields. */
  26.     /* Modules */
  27.     "module": "commonjs",                                /* Specify what module code is generated. */
  28.     // "rootDir": "./",                                  /* Specify the root folder within your source files. */
  29.     // "moduleResolution": "node",                       /* Specify how TypeScript looks up a file from a given module specifier. */
  30.     // "baseUrl": "./",                                  /* Specify the base directory to resolve non-relative module names. */
  31.     // "paths": {},                                      /* Specify a set of entries that re-map imports to additional lookup locations. */
  32.     // "rootDirs": [],                                   /* Allow multiple folders to be treated as one when resolving modules. */
  33.     // "typeRoots": [],                                  /* Specify multiple folders that act like `./node_modules/@types`. */
  34.     // "types": [],                                      /* Specify type package names to be included without being referenced in a source file. */
  35.     // "allowUmdGlobalAccess": true,                     /* Allow accessing UMD globals from modules. */
  36.     // "resolveJsonModule": true,                        /* Enable importing .json files */
  37.     // "noResolve": true,                                /* Disallow `import`s, `require`s or `<reference>`s from expanding the number of files TypeScript should add to a project. */
  39.     /* JavaScript Support */
  40.     // "allowJs": true,                                  /* Allow JavaScript files to be a part of your program. Use the `checkJS` option to get errors from these files. */
  41.     // "checkJs": true,                                  /* Enable error reporting in type-checked JavaScript files. */
  42.     // "maxNodeModuleJsDepth": 1,                        /* Specify the maximum folder depth used for checking JavaScript files from `node_modules`. Only applicable with `allowJs`. */
  44.     /* Emit */
  45.     // "declaration": true,                              /* Generate .d.ts files from TypeScript and JavaScript files in your project. */
  46.     // "declarationMap": true,                           /* Create sourcemaps for d.ts files. */
  47.     // "emitDeclarationOnly": true,                      /* Only output d.ts files and not JavaScript files. */
  48.     // "sourceMap": true,                                /* Create source map files for emitted JavaScript files. */
  49.     // "outFile": "./",                                  /* Specify a file that bundles all outputs into one JavaScript file. If `declaration` is true, also designates a file that bundles all .d.ts output. */
  50.     // "outDir": "./",                                   /* Specify an output folder for all emitted files. */
  51.     // "removeComments": true,                           /* Disable emitting comments. */
  52.     // "noEmit": true,                                   /* Disable emitting files from a compilation. */
  53.     // "importHelpers": true,                            /* Allow importing helper functions from tslib once per project, instead of including them per-file. */
  54.     // "importsNotUsedAsValues": "remove",               /* Specify emit/checking behavior for imports that are only used for types */
  55.     // "downlevelIteration": true,                       /* Emit more compliant, but verbose and less performant JavaScript for iteration. */
  56.     // "sourceRoot": "",                                 /* Specify the root path for debuggers to find the reference source code. */
  57.     // "mapRoot": "",                                    /* Specify the location where debugger should locate map files instead of generated locations. */
  58.     // "inlineSourceMap": true,                          /* Include sourcemap files inside the emitted JavaScript. */
  59.     // "inlineSources": true,                            /* Include source code in the sourcemaps inside the emitted JavaScript. */
  60.     // "emitBOM": true,                                  /* Emit a UTF-8 Byte Order Mark (BOM) in the beginning of output files. */
  61.     // "newLine": "crlf",                                /* Set the newline character for emitting files. */
  62.     // "stripInternal": true,                            /* Disable emitting declarations that have `@internal` in their JSDoc comments. */
  63.     // "noEmitHelpers": true,                            /* Disable generating custom helper functions like `__extends` in compiled output. */
  64.     // "noEmitOnError": true,                            /* Disable emitting files if any type checking errors are reported. */
  65.     // "preserveConstEnums": true,                       /* Disable erasing `const enum` declarations in generated code. */
  66.     // "declarationDir": "./",                           /* Specify the output directory for generated declaration files. */
  67.     // "preserveValueImports": true,                     /* Preserve unused imported values in the JavaScript output that would otherwise be removed. */
  69.     /* Interop Constraints */
  70.     // "isolatedModules": true,                          /* Ensure that each file can be safely transpiled without relying on other imports. */
  71.     // "allowSyntheticDefaultImports": true,             /* Allow 'import x from y' when a module doesn't have a default export. */
  72.     "esModuleInterop": true,                             /* Emit additional JavaScript to ease support for importing CommonJS modules. This enables `allowSyntheticDefaultImports` for type compatibility. */
  73.     // "preserveSymlinks": true,                         /* Disable resolving symlinks to their realpath. This correlates to the same flag in node. */
  74.     "forceConsistentCasingInFileNames": true,            /* Ensure that casing is correct in imports. */
  76.     /* Type Checking */
  77.     "strict": true,                                      /* Enable all strict type-checking options. */
  78.     // "noImplicitAny": true,                            /* Enable error reporting for expressions and declarations with an implied `any` type.. */
  79.     // "strictNullChecks": true,                         /* When type checking, take into account `null` and `undefined`. */
  80.     // "strictFunctionTypes": true,                      /* When assigning functions, check to ensure parameters and the return values are subtype-compatible. */
  81.     // "strictBindCallApply": true,                      /* Check that the arguments for `bind`, `call`, and `apply` methods match the original function. */
  82.     // "strictPropertyInitialization": true,             /* Check for class properties that are declared but not set in the constructor. */
  83.     // "noImplicitThis": true,                           /* Enable error reporting when `this` is given the type `any`. */
  84.     // "useUnknownInCatchVariables": true,               /* Type catch clause variables as 'unknown' instead of 'any'. */
  85.     // "alwaysStrict": true,                             /* Ensure 'use strict' is always emitted. */
  86.     // "noUnusedLocals": true,                           /* Enable error reporting when a local variables aren't read. */
  87.     // "noUnusedParameters": true,                       /* Raise an error when a function parameter isn't read */
  88.     // "exactOptionalPropertyTypes": true,               /* Interpret optional property types as written, rather than adding 'undefined'. */
  89.     // "noImplicitReturns": true,                        /* Enable error reporting for codepaths that do not explicitly return in a function. */
  90.     // "noFallthroughCasesInSwitch": true,               /* Enable error reporting for fallthrough cases in switch statements. */
  91.     // "noUncheckedIndexedAccess": true,                 /* Include 'undefined' in index signature results */
  92.     // "noImplicitOverride": true,                       /* Ensure overriding members in derived classes are marked with an override modifier. */
  93.     // "noPropertyAccessFromIndexSignature": true,       /* Enforces using indexed accessors for keys declared using an indexed type */
  94.     // "allowUnusedLabels": true,                        /* Disable error reporting for unused labels. */
  95.     // "allowUnreachableCode": true,                     /* Disable error reporting for unreachable code. */
  97.     /* Completeness */
  98.     // "skipDefaultLibCheck": true,                      /* Skip type checking .d.ts files that are included with TypeScript. */
  99.     "skipLibCheck": true                                 /* Skip type checking all .d.ts files. */
  100.   }
  101. }

举个例子

这里创建了一个演示用的foo函数，接收一个字符串参数bar，返回一个字符串结果。请分别用package.json里的命令来动手试一试看一看结果吧

  1. /**
  2. * 
  3. * @param {string} bar 
  4. * @return {string}
  5. */
  6. function foo(bar: string): string {
  7.   return `hello， ${bar}`;
  8. }
  10. console.log(foo('ataola'))
  11. console.log(foo('world'))

项目文件地址: https://gitee.com/taoge2021/study-typescript/tree/master/base/ts-init