The push() method adds one or more elements to the end of an array and returns the new length.
✅ Implementation
Array.prototype.customPush = function (...elements) { for (let i = 0; i < elements.length; i++) { this[this.length] = elements[i]; // Add elements at the end of the array } return this.length; // Return the new length of the array }; // Example usage: const array = [1, 2, 3]; array.customPush(4, 5); console.log(array); // Output: [1, 2, 3, 4, 5] console.log(array.customPush(6, 7)); // Output: 7 (new length of array) console.log(array); // Output: [1, 2, 3, 4, 5, 6, 7]
How It Works
- Uses the rest parameter (
...elements)- Allows multiple arguments to be passed and handled dynamically.
- Iterates over new elements
- Adds each
elementatthis.length, ensuring insertion at the end.
- Adds each
- Returns the new length
- Mimics
push()behavior by returning the updated length.
- Mimics
Edge Cases Handled
✔ Works with multiple elements: customPush(4, 5, 6)
✔ Works with an empty array: [].customPush(1, 2, 3)
✔ Works with no arguments: array.customPush() (returns unchanged length)
✔ Appends elements in order
This implementation is simple, efficient, and follows the behavior of Array.prototype.push exactly.
Quick Quiz
Test your understanding with 3 quick questions
Q1What does `push()` return?
Q2How does the push polyfill add elements to the array?
Q3What does `[1, 2].customPush(3, 4, 5)` return?