JavaScript: What and when to use Array.every() method

Posted on Feb 25, 2021

Learn what the Array.every() method do and when you need to use it

The JavaScript every() method will check if each one of your Array elements passes a certain test function that you can define as the callback function.

The every() method will return either true or false as the result of the method call. When you have even one element that doesn’t pass the test, the method will return false.

Let’s see an example of every() in action: Suppose you want to make sure that an array of ages are all above 20.

Here’s how to find out with every():

let ages = [22, 29, 25];

let isAgesAboveTwenty = ages.every((element) => element > 20);

console.log(isAgesAboveTwenty); // true

Again, when you have an element that doesn’t pass the test, every() will stop the execution and immediately returns false:

let ages = [17, 29, 25];

let isAgesAboveTwenty = ages.every((element) => {
  console.log(element);
  element > 20;
});

console.log(isAgesAboveTwenty); // false

The above code will log only 17 and false to the console. The rest of the elements are not checked again.

JavaScript every() method is used only when you want to know whether all elements in your array pass a certain test. While you can certainly implement the same test using for loop or forEach method, the every() method is a built-in method that’s readily available for all your Array type objects.

By using every(), you reduce the amount of code you need to write in your program.

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