Accessor Methods (concat, slice, join, indexOf, lastIndexOf, includes)

Accessor methods do not modify the original array; they return a new array or a value derived from the array.

Common Accessor Methods

Method	Description
concat()	Merges two or more arrays and returns a new array.
slice()	Extracts a portion of the array and returns a new array.
join()	Joins all elements into a string.
indexOf()	Returns the first index where a value is found; -1 if not found.
lastIndexOf()	Returns the last index where a value is found.
includes()	Checks if a value exists in the array.

Code Example

const arr = [1, 2, 3, 4, 2];

const newArr = arr.concat([5, 6]); // [1,2,3,4,2,5,6]
const sliced = arr.slice(1, 4); // [2,3,4]
const str = arr.join("-"); // "1-2-3-4-2"

console.log(arr.indexOf(2)); // 1
console.log(arr.lastIndexOf(2)); // 4
console.log(arr.includes(3)); // true
console.log(arr.includes(5)); // false

// Original array unchanged
console.log(arr); // [1, 2, 3, 4, 2]