#no-await-in-loop

#Configuration

import { defineConfig, js } from '@rslint/core';

export default defineConfig([
  js.configs.recommended,
  {
    rules: {
      'no-await-in-loop': 'error',
    },
  },
]);

#Rule Details

Disallows await expressions inside loop bodies (for, for-in, for-of, while, do-while). Using await in a loop is usually a sign that the program is not taking full advantage of the parallelization benefits of async/await, as each iteration waits for the previous one to complete. The operations can often be refactored to use Promise.all() instead.

This rule allows await in for-await-of loops, since those are designed to work with async iterables. However, a for-await-of nested inside another loop will be flagged.

Examples of incorrect code for this rule:

async function foo(things) {
  for (const thing of things) {
    await bar(thing);
  }
}

async function foo(things) {
  while (things.length) {
    await bar(things.pop());
  }
}

Examples of correct code for this rule:

async function foo(things) {
  await Promise.all(things.map((thing) => bar(thing)));
}

async function foo(things) {
  for await (const thing of asyncIterable) {
    console.log(thing);
  }
}

#Original Documentation

• ESLint no-await-in-loop