Determine whether all array elements are same in JavaScript

This post will discuss how to determine whether all array elements are same or not in JavaScript.

There are several ways to determine whether all array elements are same or not in JavaScript. Here are some of the possible functions, along with some examples:

1. Using `Array.every()` function

The Array.every() function tests whether all elements in the array pass a test implemented by a provided function. We can pass a function that compares each element of the array to the first element, using the strict equality operator (===). This will return true if all elements are equal, and false otherwise. Here’s an example:

function allEqual(arr) {

return arr.every(val => val === arr[0]);

}

console.log(allEqual([1, 1, 1])); // true

console.log(allEqual([1, 2, 1])); // false

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2. Using a Set

The Set object allows us to store unique values of any type. To use it, we need to create a new Set object from the array using the new Set() constructor. This will eliminate any duplicate values from the array. Then, we can check the size property of the Set object, which returns the number of values in the Set. If the size is 1, it means all elements in the array are equal. If the size is greater than 1, it means there are different elements in the array. For instance:

function allEqual(arr) {

return new Set(arr).size === 1;

}

console.log(allEqual([1, 1, 1])); // true

console.log(allEqual([1, 2, 1])); // false

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3. Using a for loop

This function iterates over the array and compares each element with the first element using the strict equality operator (===). The idea is to use a flag variable to indicate whether the array is identical or not, and initialize it to true. Then, we need to loop over the array from the second element onwards, and update the result variable with the comparison result. If any comparison returns false, the result variable will become false as well. After the loop ends, we can return the result variable. For instance:

function allEqual(arr)

{

// if the array is empty or has one element, it is equal

if (arr.length <= 1) {

return true;

}

// store the first element as a reference

let first = arr[0];

// loop through the rest of the array

for (let i = 1; i < arr.length; i++)

{

// if any element is not equal to the first one, return false

if (arr[i] !== first) {

return false;

}

// if the loop finishes without returning false, return true

return true;

}

console.log(allEqual([1, 1, 1])); // true

console.log(allEqual([1, 2, 1])); // false

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That’s all about determining whether all array elements are same or not in JavaScript.

Determine whether all array elements are same in JavaScript

1. Using Array.every() function

2. Using a Set

3. Using a for loop

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1. Using `Array.every()` function