Extract Keys

Rendering Listseasy

Course · Section 11: Working With Arrays · Lecture 157: The map Method

Implement `getKeys(items)` returning the `id` of each item, suitable for React list keys.

Input: getKeys([{"id":3},{"id":7}])

Output: [3,7]

Input: getKeys([])

Output: []

+ 1 hidden test run on Submit.

Common pitfalls

Using array index as a key when items reorder, which breaks reconciliation; prefer stable ids.

Approach & explanation (try first)

Extracting stable ids gives React keys that survive reordering, so it can match elements across renders correctly.

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