#no-unneeded-async-expect-function

#Configuration

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

export default defineConfig([
  jestPlugin.configs.recommended,
  {
    rules: {
      'jest/no-unneeded-async-expect-function': 'error',
    },
  },
]);

#Rule Details

Disallow wrapping an expected promise in an unnecessary async function when using Jest promise assertions.

Jest promise assertions can receive the promise directly: await expect(doSomethingAsync()).rejects.toThrow() or await expect(doSomethingAsync()).resolves.toBe(value). Wrapping that call in async () => { await doSomethingAsync(); } is more verbose and makes the test harder to read without changing the assertion.

This rule reports expect() calls whose first argument is an async function with a single awaited call expression. It is fixable: the async wrapper is replaced with the awaited call. Renamed expect bindings imported from @jest/globals are also recognized.

Examples of incorrect code for this rule:

it('wrong1', async () => {
  await expect(async () => {
    await doSomethingAsync();
  }).rejects.toThrow();
});

it('wrong2', async () => {
  await expect(async function () {
    await doSomethingAsync();
  }).rejects.toThrow();
});

Examples of correct code for this rule:

it('right1', async () => {
  await expect(doSomethingAsync()).rejects.toThrow();
});

#Differences from ESLint

rslint also fixes equivalent concise arrow functions and parenthesized async function arguments, such as expect(async () => await doSomethingAsync()) and expect((async () => { await doSomethingAsync(); })). These shapes are handled as the same safe unwrap because tsgo preserves them explicitly in the AST.

#Original Documentation

• jest/no-unneeded-async-expect-function