每晚等待 Node 17 和 TypeScript 的顶级

Question

我有一个简单的脚本试图用 Node 和 TypeScript 测试顶级 await。

import { readFile } from "fs/promises";

async function getNum(filename: string) {
  return parseInt(await readFile(filename, "utf8"), 10);
}

try {
  const numberPromises = [1, 2, 3].map((i) => getNum(`${i}.txt`));
  const numbers = await Promise.all(numberPromises);
  console.log(numbers[0], numbers[1], numbers[2]);
} catch (err) {
  console.error("Something went wrong");
  console.error(err);
}

当我尝试使用 TypeScript 编译时出现此错误：

error TS1378: Top-level 'await' expressions are only allowed when the 'module' option is set to 'es2022', 'esnext', 'system', or 'nodenext', and the 'target' option is set to 'es2017' or higher.

第9行顶层await触发：

const numbers = await Promise.all(numberPromises);

我很困惑，因为我已经完成了错误消息中提到的两件事，并且我已尝试尽可能地配对我的 tsconfig.json。

{
  "compilerOptions": {
    "module": "es2022",
    "target": "es2017",
    "outDir": "dist",
    "strict": true,
    "moduleResolution": "Node"
  }
}

我的 package.json 文件中也有 type: module。

{
  "name": "ts-test",
  "version": "1.0.0",
  "type": "module",
  "devDependencies": {
    "@types/node": "^17.0.5",
    "typescript": "^4.6.0-dev.20211226"
  },
  "scripts": {
    "dev": "node dist/script.js",
    "compile": "tsc script.ts"
  },
  "author": "Todd Matthews",
  "license": "ISC",
  "volta": {
    "node": "17.3.0"
  }
}

任何关于如何使用 Node 和 TypeScript 测试顶级 await 的帮助都将不胜感激！

Answer 1

我会为你提供一个不依赖任何文件系统的更简单的复现案例API，我会包括所有的repo文件和命令：

文件

./package.json:

{
  "name": "so-70491077",
  "version": "1.0.0",
  "description": "",
  "type": "module",
  "main": "dist/main.ts",
  "scripts": {
    "test": "tsc && node dist/main.js"
  },
  "author": "",
  "license": "MIT",
  "devDependencies": {
    "typescript": "^4.5.4"
  }
}

./tsconfig.json:

{
  "compilerOptions": {
    "module": "es2022",
    "target": "es2017",
    "outDir": "dist",
    "strict": true,
    "moduleResolution": "Node"
  },
  "files": ["main.ts"]
}

./main.ts:

export async function getRandom (): Promise<number> {
  return Math.random();
}

const n = await getRandom();
console.log(n);

命令

cd /path/to/the/dir/where/you/stored/the/files/above
npm i
npm test

输出

> so-70491077@1.0.0 test
> tsc && node dist/main.js

0.9303778211654203 # a similar floating point number

Answer 2

您的代码和 tsconfig.json 没问题。但是 tsc 不使用 tsconfig.json 文件。来自文档 What is a tsconfig.json:

When input files are specified on the command line, tsconfig.json files are ignored.

因此，不要为 compile npm 脚本指定输入文件。

"scripts": {
   "compile": "tsc"
}

每晚等待 Node 17 和 TypeScript 的顶级

Top-level Await Node 17 & TypeScript nightly

node.js

async-await

typescript

文件

命令

输出