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如何在TypeScript中实现ES2018目标?

  •  3
  • mikemaccana  · 技术社区  · 7 年前

    我的目标是ES2018,不关心ES3或ES5。来自my tsconfig.json: "target": "ES2018" . tsc 抱怨:

    ES5/ES3中的异步函数或方法需要“Promise”构造函数。制造 当然你有一个“Promise”构造函数的声明,或者在你的 --lib 选择。

    我知道我可以加上 "lib": ["es2015"] 将库添加到编译中,但是 我不需要那些图书馆,我的目标是ES2018 .

    如何在TypeScript中实现ES2018目标?

    {
        "compilerOptions": {
                /* Basic Options */
                "target": "ES2018" /* 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": ["es2015"] /* 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. */
        }
    }
    
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  •  3
  •   weakish    7 年前

    只需添加 ES2018 lib 在里面 tsconfig.json :

    "lib": [
      "ES2018"
    ]
    

    图书馆 不同于 target . 目标 大致是指生成的输出文件的JavaScript版本。 图书馆 表示将在TypeScript中使用的功能。例如,您可以在ES2018中使用新功能( "lib": ["ES2018"] ),但仍以ES6为目标(“target”:“ES6”)。这些新特性将在编译期间转换为ES6(这可以通过第三方工具如babel来完成,但这只是实现细节)。但是要小心,并不是所有的新特性都是可翻译的。