Array.prototype.keys() - JavaScript | MDN

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Using keys() on sparse arrays

Unlike Object.keys(), which only includes keys that actually exist in the array, the keys() iterator doesn't ignore holes representing missing properties.

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This page was last modified on Jul 20, 2025 by MDN contributors.

[Symbol.unscopables]

[Symbol.hasInstance]()

__defineGetter__()

__defineSetter__()

__lookupGetter__()

__lookupSetter__()

propertyIsEnumerable()