Move Item

Immutable Arraysmedium

Course · Section 9: Data Structures, Modern Operators and Strings · Lecture 111: The Spread Operator (...)

Implement `moveItem(list, from, to)` returning a new array with the element at `from` moved to index `to` (useful for drag-and-drop lists).

Sample tests

Input: moveItem([1,2,3,4], 0, 2)

Output: [2,3,1,4]

Input: moveItem(["a","b"], 1, 0)

Output: ["b","a"]

+ 1 hidden test run on Submit.

Hints

Common pitfalls

Calling splice directly on the state array mutates it.
Inserting before removing, which shifts the indices and moves the wrong element.

Learning resources

React: Updating Arrays in State

Approach & explanation (try first)

Work on a copy made with [...list]. splice(from, 1) removes and returns the moved element; splice(to, 0, moved) inserts it at the destination. Because all of this happens on the copy, the original array is never touched.

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Run your code to see results.

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