JavaScript: Check whether all elements in a given array are equal or not

JavaScript fundamental (ES6 Syntax): Exercise-56 with Solution

Check All Elements Equal in Array

Write a JavaScript program to check whether all elements in a given array are equal or not.

• Use Array.prototype.every() to check if all the elements of the array are the same as the first one.
• Elements in the array are compared using the strict comparison operator, which does not account for NaN self-inequality.

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2
// Define a function 'allEqual' to check if all elements in the array are equal.
const allEqual = arr =>
  // Use the 'every' method to check if all elements in the array are equal to the first element.
  arr.every(val => val === arr[0]);

// Test cases
console.log(allEqual([1, 2, 3, 4, 5, 6])); // Output: false (not all elements are equal)
console.log(allEqual([12, 12, 12, 12]));    // Output: true (all elements are equal)

Output:

false
true

Visual Presentation:

Flowchart:

Live Demo:

See the Pen javascript-basic-exercise-56-1 by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

• Write a JavaScript program that returns true if every element in an array is identical.
• Write a JavaScript function that compares each array element with the first element and returns a boolean result.
• Write a JavaScript program that checks an array’s homogeneity by using the Array.every() method.

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