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How Can I Efficiently Add Elements to the Beginning of a JavaScript Array?
How Can I Efficiently Add Elements to the Beginning of a JavaScript Array?
Nov 27, 2024 am 06:28 AM
Prepending Elements to an Array in JavaScript
To add new elements to the beginning of an array, you can leverage JavaScript's built-in unshift method, which offers an efficient O(1) operation. This method takes any number of arguments and inserts them as new elements at the start of the array.
Usage:
array.unshift(element1, element2, ...)
Example:
Consider an array [23, 45, 12, 67]. To prepend the element 34, simply call:
array.unshift(34);
The resulting array will be [34, 23, 45, 12, 67], as desired.
Comparison to Previous Approach:
Your initial approach of creating a new array, pushing the new element, and then concatenating the old array is not only complex (O(n)) but also unnecessary. unshift achieves the same result with significantly better efficiency.
Additional Notes:
- unshift can also be used to add multiple elements at once.
- For adding elements to the end of an array, use the push method.
- For removing elements from the beginning or end of an array, use shift and pop respectively.
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