prefer-array-flat-map

Configuration

rslint.config.ts

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

export default defineConfig([
  unicornPlugin.configs.recommended,
  {
    rules: {
      'unicorn/prefer-array-flat-map': 'error',
    },
  },
]);

Rule Details

Prefer Array#flatMap() over chaining Array#map() and Array#flat() when the flat depth is omitted or exactly 1.

Examples of incorrect code for this rule:

const foo = bar.map(element => unicorn(element)).flat();
const foo = bar.map(element => unicorn(element)).flat(1);

Examples of correct code for this rule:

const foo = bar.flatMap(element => unicorn(element));
const foo = bar.map(element => unicorn(element)).flat(2);
const foo = React.Children.map(children, fn).flat();

Original Documentation