Pattern: Legacy array flattening technique
Issue: -
ES2019's Array#flat() method provides a cleaner way to flatten arrays compared to older techniques like reduce(), concat(), or spread operators.
Example of incorrect code:
const foo = array.reduce((a, b) => a.concat(b), []);
const foo = array.reduce((a, b) => [...a, ...b], []);
const foo = [].concat(...array);
const foo = [].concat.apply([], array);
const foo = Array.prototype.concat.apply([], array);Example of correct code:
const foo = array.flat();
const foo = [maybeArray].flat();