JavaScript Array some() method explained with code examples

The JavaScript Array some() method is used to test if an array has at least one element that meets a specific condition.

To use the some() method, you need to pass the test as a function that will be run against each element in the array.

For example, suppose you want to test if an array has an element that’s greater than 4. Here’s how you do it:

const numbers = [1, 2, 3, 4, 5];

const testResult = numbers.some(function (element) {
  return element > 4;
});

console.log(testResult); // true

The some() method will pass each element in the array into the function passed as its argument.

When one of the tested elements returns true, then some() will return true; otherwise, the method returns false.

You can read the some() method as check if some elements in this array meet a specific condition, with the condition passed as its argument.

The syntax of the some() method is as follows:

Array.some(function (element, index, array) {
  // function body
}, thisArg);

The function you passed as an argument to the some() method will be executed with three arguments:

• The element from the array
• The index of that element
• And the array object where the method is called from

The thisArg argument passed after the function is used to change the context of the this keyword inside the function body.

When defining the some() method, only the element argument is required. The index, array, and thisArg arguments are optional.

Code examples of some() method in action

The following example tests if any element in the array equals a specific value:

const animals = ["dog", "cat", "horse"];

const result = animals.some(function (element) {
  return element === "horse";
});

console.log(result); // true

So far, the examples used an anonymous function as the argument for the some() method, but you can also use an [arrow function( https://sebhastian.com/arrow-function-javascript/ )] or named function as shown below:

[7, 57, 83, 101].some(element => element < 5); // false

[7, 57, 83, 101].some((element, index, array) => {
  return element > 5;
}); // true

// Using a named function
function lessThanTen(element, index, array) {
  return element < 10;
}

[7, 57, 83, 101].some(lessThanTen); // true

// Using a named arrow function
const greaterThanHundred = element => element > 100;

[7, 57, 83, 101].some(greaterThanHundred); // true

When you execute the some() method against an empty array, the method will always return false regardless of the condition you specified.

Consider the following code examples:

[].some(el => el === null); // false
[].some(el => el === undefined); // false
[].some(el => el > 2); // false

Finally, you can also check if a number in your array is within a specific range with some() method.

The code below tests if any element in the array is between 30 to 50:

const scores = [25, 55, 72, 85];

const result = scores.some(function (el) {
    return el >= 30 && el <= 50;
});

console.log(result); // false

The function provided as the argument to the some() method can be as creative as you need it to be.

The only rule is that the function must return a boolean value (true or false)

Now you’ve learned how the some() method of the JavaScript Array object works. Nice work! 😉