Deep clone a value

Medium25 minFree, no account

Six lines get you 80%. The cycle and the Date get you the other 20%.

The question

Write deepClone(value) that handles nested objects and arrays, Date, Map, Set, and circular references.

The clone must share no mutable structure with the original.

const a = { d: new Date(), s: new Set([1, 2]), list: [1, [2, 3]] };
a.self = a;

const b = deepClone(a);
b.self === b          // true, the cycle is preserved, not followed
b.d instanceof Date   // true, not a string
b.list[1] !== a.list[1]

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The worked solution

written by a person · not a grade

Score yourself

0 of 5 marked

Rejected the JSON approach with specific reasons15
Correct recursion over objects and arrays25
Cycles handled with a WeakMap registered before recursing30
Date, Map and Set handled as themselves20
Stated complexity and the recursion-depth limit10

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