Shallow Copy with Spread

Behind the Scenesmedium

Course · Section 8: How JavaScript Works Behind the Scenes · Lecture 104: Object References in Practice (Shallow vs. Deep Copies)

Implement `copyWith(obj, key, value)` returning a shallow copy of `obj` with `key` set to `value`, without mutating the original.

Input: copyWith({"a":1}, "b", 2)

Output: {"a":1,"b":2}

Input: copyWith({"a":1}, "a", 9)

Output: {"a":9}

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Common pitfalls

Approach & explanation (try first)

Spreading creates a new top-level object; nested values would still be shared references.

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