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Implement Array.prototype.reduce

By FrontendAtlas Team · Updated Jan 31, 2026

Recreate the native .reduce() method without using it. Your myReduce must call the reducer with (accumulator, currentValue, index, array) only for existing indices, handle an optional initialValue, and return the final accumulator. If no initialValue is provided, use the first existing element as the initial…

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Implement Array.prototype.reduce: Recreate the native .reduce() method without using it. Your myReduce must call the reducer with (accumulator, currentValue, index, array) only for existing indices, handle…. Expect arrays and callbacks decisions under intermediate level constraints.

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