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Make Counter — JavaScript Challenge | FineFrontend

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JavaScript/Make Countereasy

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JavaScript interview question

easy10 min

Create an independent counter function that returns its starting value, then increases by one on each call.

Implement makeCounter(initialValue = 0), returning a callable counter.
The first call returns initialValue. Each subsequent call returns the previous result plus one.
Each counter has independent state. Support zero, positive, and negative integer starting values.
Do not use global state or mutate any external object.

Example 1

Input: const next = makeCounter(5); [next(), next(), next()]
Output: [5, 6, 7]

Create an independent counter function that returns its starting value, then increases by one on each call.

What the tests check

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