prefer-array-flat-map.md

prefer-array-flat-map

📝 Prefer .flatMap(…) over .map(…).flat().

💼 This rule is enabled in the following configs: ✅ recommended, ☑️ unopinionated.

🔧 This rule is automatically fixable by the --fix CLI option.

Array#flatMap performs Array#map and Array#flat in one step.

Examples

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

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

// ✅
const foo = bar.flatMap(element => unicorn(element));

// ✅
const foo = bar.map(element => unicorn(element)).flat(2);

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

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

Related rules

• unicorn/prefer-array-flat