deep-clone.md

Deep Clone

Task: "Deep clone this object."

Without Ponytail

npm install lodash

import { cloneDeep } from "lodash";

const copy = cloneDeep(original);

Or the classic hack:

// fragile: loses Date, undefined, Map, Set, circular refs, functions
const copy = JSON.parse(JSON.stringify(original));

With Ponytail

// ponytail: structuredClone does this
const copy = structuredClone(original);

1 dependency (or a fragile hack) → 1 built-in. structuredClone handles Date, Map, Set, ArrayBuffer, RegExp, circular references, and more, everything JSON.parse/stringify silently drops. Available in every browser since 2022 and Node.js since v17. Pull lodash in when you need the rest of it, not for one function.