Question

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

ES5 / ES3中的异步函数或方法需要'Promise'构造函数。使确保您已声明“ Promise”构造函数，或在--lib选项中包含“ ES2015”。

我知道我可以添加"lib": ["es2015"]来向编译中添加库，但是我不需要这些库，我的目标是ES2018 。

如何在TypeScript中定位ES2018？

{
    "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. */
    }
}

Answer 1

只需将ES2018添加到lib中的tsconfig.json：

"lib": [
  "ES2018"
]

lib与target不同。 target大致表示生成的输出文件的JavaScript版本。 lib表示您将在TypeScript中使用的功能。例如，您可以在ES2018（"lib": ["ES2018"]）中使用新功能，但仍以ES6（`“ target”：“ ES6”）为目标。这些新功能将在编译期间转换为ES6（这可以通过第三方工具（如babel）完成，但这只是实现细节）。但是请注意，并非所有新功能都是可翻译的。

如何在TypeScript中定位ES2018？

1 个答案: