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JavaScript: Scripting language
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When you delete an array element, the array length is not affected. This holds even if you delete the last element of the array.
When you delete an array element, the array length is not affected. This holds even if you delete the last element of the array.
Deleting non-configurable properties
When a property is marked as non-configurable, delete won't have any effect, and will return false. In strict mode, this will raise a TypeError.
If a global property is configurable (for example, via direct property assignment), it can be deleted, and subsequent references to them as global variables will produce a ReferenceError.
This page was last modified on Jul 17, 2025 by MDN contributors.