JavaScript Array some() Method

What is Array some() in Javascript?

The some in javascript take a callback function and executes it for every element present in the array. The execution happens until someone in javascript finds an element that returns true for the callback function, i.e. until it finds an element that satisfies the condition within the callback function. If the value is found, the execution of the function stops, and it returns true. If no such element exists in the array, the some in javascript return false.

Following are some points that should be noted about the some in JavaScript:

• The range of the elements should be set before the some method is called for the first time.
• The callback function wouldn't visit the elements that were added after the some() method was invoked.
• The some in javascript doesn't work on the deleted array elements.
• If an element is changed by the callback function, the new changed value gets defined to the array.
• The callback function never gets invoked for the indexes that have been deleted or which have never been assigned values.

Example

Output:

Explanation of the example

In the above example, we have declared two arrays, arr1 and arr2. Now, we have declared a function isOdd, which takes a parameter item. The item % 2 !== 0 checks if an item is odd, if it is odd then it returns true otherwise false.

When the some method is run on arr1, since 25 is odd thus some will stop execution and return true.

When the some method is run on arr2, since there is no odd number present in the array thus some will stop execution and return true.

Syntax of Array some() in Javascript

The following is the syntax of Array some() in javascript:

Here arr is the array upon which the some in javascript is running the test.

In the above code, we have done three types of declaration:
(i) With the help of the arrow function.
(ii) with the help of the inline function.
(iii) with the help of the inline function.

Parameters of Array some() in Javascript

The following are the parameters of Array some() in javascript:

• callbackFn: This is a mandatory parameter. This parameter accepts a function that is used to test the elements of the array.
• Element: This is a mandatory parameter. This parameter refers to the element that is currently being processed in the array, i.e., the elements that are currently passed as a parameter to the test.
• Index: This is a mandatory parameter. This parameter refers to the index of the element that is currently being processed in the array, i.e., the elements that are currently passed as a parameter to the test.
• Array: This is a mandatory parameter. This parameter refers to the array upon which the test is run by some in javascript.
• thisArg: This is an optional parameter. This parameter acts as a value that can be used when the callbackFn is executed.

Return Value of Array some() in Javascript

Return Type: boolean

The some in javascript returns true if the test is true for at least one element in the array; otherwise it returns false.

More Examples

Example 1: Checking whether a value exists in an array

Output:

Explanation

In the above example, we are declaring an array of languages. Now, the function is present takes two parameters arr and val and returns true if val is the same as at least one element in the array, otherwise it will return false.

Here,

is the test which checks if an element of the array is equal to val.

Inthe the first case, the parameters are languages, kotlin. Since languages do not contain kotlin thus, it will return false.

In the second case, the parameters are languages, python. Since languages do contains kotlin thus, it will return true.

Example 2: Converting any value to Boolean

Output:

Explanation

In the above example, we have declared an array arr. Here, in this case, we are taking the input, and then the value is compared into a boolean value. Then arr. some is used to compare that boolean value with the array elements and return true or false.

Browser compatibility

The some method in javascript is supported by all the browsers such as Chrome, Edge, Safari, Opera, etc.