如何在打字稿中使用顶级异步等待？

Question

我有一个打字稿项目，当我await xxx.someAsyncMethod(..)在顶层使用时，打字稿短绒显示，

Top-level 'await' expressions are only allowed when the 'module' option is set to 'esnext' or 'system', and the 'target' option is set to 'es2017' or higher.

所以我将模块更改为 esnext "module": "esnext"

我会继续尝试运行该程序 npx ts-node app/app.ts

然后控制台通知我

(node:15509) Warning: To load an ES module, set "type": "module" in the package.json or use the .mjs extension.
Cannot use import statement outside a module

"type": "module"当我运行控制台输出的程序时，在 package.json 中将类型设置为模块

TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".ts" for /Users/apple/Desktop/source_given_to_me/Git/bots/wab/app/app.ts
    at Loader.defaultGetFormat [as _getFormat] (internal/modules/esm/get_format.js:65:15)
    at Loader.getFormat (internal/modules/esm/loader.js:113:42)
    at Loader.getModuleJob (internal/modules/esm/loader.js:244:31)
    at Loader.import (internal/modules/esm/loader.js:178:17)

我可以做些什么来逃避使用顶级异步等待？

编辑： 我的 redis.ts 文件

import * as pm from "child_process"
var prc:pm.ChildProcess;

async function startRedis(path:string): Promise<boolean> {
    return new Promise((resolve) => {
        console.log('starting redis')
        var rp = pm.spawn(path)
        rp.stdout.on("data", (data) => {
            console.log(data)
            console.log('redis fired up')
            prc= rp
            resolve(true)
        })
        rp.stderr.on("data", (data) => {
            console.log(data)
            console.log('redis failed to start')
            resolve(false)
        })
    })
}

function active():boolean{
    return prc?!prc.killed:false
}

async function stopRedis(): Promise<boolean> {
    return new Promise(
        (resolve)=>{
            if(prc){
                resolve(prc.kill("SIGTERM"))
            } else {
                resolve(false)
            }
        }
    )
}


export const redis = {
    startRedis,
    stopRedis,
    active
}

我的 config.ts 文件（tsconfig.json 在下面）

export const config = {
    redisPath:'../r607/src/redis-server'
}

我的 app.ts 文件

import {config} from "./config.js"
import {redis} from "./redis.js"
//import * as pm from "child_process"

await redis.startRedis(config.redisPath)
if(!redis.active()){
    process.abort()
}

我的 tsconfig.json

{
  "compilerOptions": {
    /* Visit https://aka.ms/tsconfig.json to read more about this file */

    /* Basic Options */
    // "incremental": true,                   /* Enable incremental compilation */
    "target": "esnext",                          /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', 'ES2018', 'ES2019', 'ES2020', or 'ESNEXT'. */
    "module": "ESNext",                     /* 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": "./build",                        /* 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 */
    "skipLibCheck": true,                     /* Skip type checking of declaration files. */
    "forceConsistentCasingInFileNames": true  /* Disallow inconsistently-cased references to the same file. */
  }
}

Answer 1

按着这些次序：

\n

\n
• 添加"type": "module"到您的 package.json。
\n
• 替换"main": "index.js"为"exports": "./index.js"package.json 中的。
\n
• 将 package.json 中的字段更新"engines"为 Node.js 12: "node": "^12.20.0 || ^14.13.1 || >=16.0.0"。
\n
• 添加"module": "ES2020"到您的 tsconfig.json。
\n
• 仅使用完整的相对文件路径进行导入：import x from \'.\';\xe2\x86\x92 import x from \'./index.js\';。
\n
• 删除namespace用法并export改为使用。
\n
• 可选但建议使用该node:协议进行导入。
\n
• .js即使您正在导入文件，也必须在相对导入中使用扩展名.ts。
\n

\n

如果您使用 ts-node\n，请像以下那样使用它：

\n

node --loader ts-node/esm ./entrypoint.ts\n

\n

编辑：\n来源要点

\n

Answer 2

您可以使用此模式获得相同的结果：

async function main(): Promise<void> {
    const foo = await somePromise
    console.log(foo)
}

main()

即使您没有await执行 main，NodeJS 也不会退出，直到事件队列为空。换句话说，当有未解决的承诺时它不会退出。