sveltekit-superforms/dist/justClone.js

Making SvelteKit forms a pleasure to use!

/*
  Deep clones all properties except functions

  var arr = [1, 2, 3];
  var subObj = {aa: 1};
  var obj = {a: 3, b: 5, c: arr, d: subObj};
  var objClone = clone(obj);
  arr.push(4);
  subObj.bb = 2;
  obj; // {a: 3, b: 5, c: [1, 2, 3, 4], d: {aa: 1}}
  objClone; // {a: 3, b: 5, c: [1, 2, 3], d: {aa: 1, bb: 2}}
*/
export function clone(obj) {
    const type = {}.toString.call(obj).slice(8, -1);
    if (type == 'Set') {
        // @ts-expect-error Known type
        return new Set([...obj].map((value) => clone(value)));
    }
    if (type == 'Map') {
        // @ts-expect-error Known type
        return new Map([...obj].map((kv) => [clone(kv[0]), clone(kv[1])]));
    }
    if (type == 'Date') {
        // @ts-expect-error Known type
        return new Date(obj.getTime());
    }
    if (type == 'RegExp') {
        // @ts-expect-error Known type
        return RegExp(obj.source, obj.flags);
    }
    if (type == 'Array' || type == 'Object') {
        const result = type == 'Object' ? Object.create(Object.getPrototypeOf(obj)) : [];
        for (const key in obj) {
            result[key] = clone(obj[key]);
        }
        return result;
    }
    // primitives and non-supported objects (e.g. functions) land here
    return obj;
}