Difference between every() and some() methods in JavaScript

JavaScript has many useful methods that can work easily with the arrays. Some of these are map(), pop(), filter() and push(). JavaScript also has some() and every() methods. The main difference between the mentioned methods is that the some() method is used for finding at least one or more than one value in the array according to the passed condition, whereas the every() method checks whether all elements of an array are satisfying the given condition or not.

This post will practically demonstrate the difference between every() and some() method using appropriate examples. So, let’s start!

every() Method in JavaScript

every() method in JavaScript is used to check whether all elements of an array are satisfying the given condition or not. If even a single value does not satisfy the element the output will be false otherwise it will return true. It is opposed to some() method.

Syntax

The general syntax of every() method is:

array.every(callback(currentvalue, index, arr), thisArg)

In JavaScript, every() method returns a Boolean value (true/false) as output.

Parameters

“callback” is a function that will test the condition.
“currentvalue” shows the current element of the array and it is required.
“index” represents the index of the current element of the array and it is optional.
“arr” is an optional parameter and demonstrates the array where the current element belongs.
“thisArg” is an optional parameter and its value is used while executing the callback function.

Now, let’s check out an example for understanding the usage of every() method in JavaScript.

How to use every() method in JavaScript

In this section, we will demonstrate the usage of every() method in JavaScript. For this purpose, consider the following array of integer values:

let arr = [1, 2, 3, 4, 5, 6, 7, 8 ];

We will now use every() method to check whether the given array has a positive value or not:

arr.every((value)=> {

return (value > 0);

});

The given array that we passed to the every() method has positive values so the condition is satisfied and the output will be true otherwise it will return false as an output if the given condition is not satisfied:

some() Method in JavaScript

The some() method is used with arrays in JavaScript. It accepts the Boolean expression (true/false) and is used to check if at least one or more than one element in the array satisfies the passed condition or not.

Syntax

The general syntax of some() method is:

array.some(function(value, index, arr), this)

In JavaScript, some() method also returns a Boolean value (true/false) as output.

Parameters

“function” executes for every element of the array.
“value” shows the current element of the array and it is required.
“index” refers to the index of the current array element and is an optional parameter.
“arr” refers to the array where the current element belongs and it is also an optional parameter.

These parameters are optional and the boolean expression that it accepts is as follows:

(element) => Boolean

The “element” denotes the current element in the array that is being checked. The “boolean” returns the Boolean value either true or false.

How to use some() method in JavaScript

Now, consider the following array of integer values:

let arr =[ 2, 3, 4, 5, 6, 7, 8];

Next, we will check if there is at least or more than one even element is in the array by using the some() method:

arr.some((value) => { return (value%2 == 0); });

The some() method will find at least or more than one even element from a given array and the output will be true because the given list has four even elements that are divisible by 2:

We have disscussed the difference between some() and every() method, their syntax and example.

Conclusion

In JavaScript, main difference between the every() and some() methods is that the some() method is used for finding at least one or more than one value in the array according to the passed condition, whereas, the every() method check whether all elements of an array are satisfying the given condition or not. This post illustrates the difference between every() and some() methods in JavaScript, its syntax with examples.