Day-36 JavaScript Array Methods You Should Know

Arrays in JavaScript are powerful and come with many built-in methods that make working with lists much easier. Today, we’re going to break down some of the most commonly used array methods: push, pop, shift, unshift, splice, slice, concat, indexOf, reverse, and sort.

1. push() – Add to the End

Usage: Adds one or more elements to the end of the array.

let fruits = ["apple", "banana"]; fruits.push("orange"); // ["apple", "banana", "orange"] 

2. pop() – Remove from the End

Usage: Removes the last element of the array.

let fruits = ["apple", "banana", "orange"]; fruits.pop(); // ["apple", "banana"] 

3. shift() – Remove from the Start

Usage: Removes the first element of the array.

let fruits = ["apple", "banana"]; fruits.shift(); // ["banana"] 

4. unshift() – Add to the Start

Usage: Adds one or more elements to the beginning of the array.

let fruits = ["banana"]; fruits.unshift("apple"); // ["apple", "banana"] 

5. splice() – Add/Remove Anywhere

Usage: Changes the contents of an array by removing or replacing elements.

let colors = ["red", "green", "blue"]; colors.splice(1, 1, "yellow"); // ["red", "yellow", "blue"] 

Syntax: splice(start, deleteCount, item1, item2, ...)

6. slice() – Copy a Portion

Usage: Returns a shallow copy of a part of an array.

let fruits = ["apple", "banana", "cherry"]; let copy = fruits.slice(1, 3); // copy = ["banana", "cherry"] 

7. concat() – Merge Arrays

Usage: Joins two or more arrays.

let a = [1, 2]; let b = [3, 4]; let result = a.concat(b); // [1, 2, 3, 4] 

8. indexOf() – Find Position

Usage: Returns the index of the first occurrence of a value.

let colors = ["red", "green", "blue"]; colors.indexOf("green"); // 1 

9. reverse() – Reverse Order

Usage: Reverses the array in place.

let numbers = [1, 2, 3]; numbers.reverse(); // [3, 2, 1] 

10. sort() – Sort Elements

Usage: Sorts the elements of an array.

let nums = [5, 1, 10]; nums.sort(); // [1, 10, 5] – be careful! It sorts as strings by default 

Tip: For numbers, use:

nums.sort((a, b) => a - b); // [1, 5, 10] 

Conclusion

These array methods are the foundation for working with lists in JavaScript. Practice them, play around with combinations, and soon they’ll become second nature.