See MDN:
The some() method executes the callbackFn function once for each element present in the array until it finds the one where callbackFn returns a truthy value (a value that becomes true when converted to a Boolean). If such an element is found, some() immediately returns true. Otherwise, some() returns false. callbackFn is invoked only for indexes of the array with assigned values. It is not invoked for indexes which have been deleted or which have never been assigned values.
You can see that here:
const arr = ['item 1', 'item 2', , 'item 3', , 'item 4', 'item 5'];
console.log(arr.some((item, index) => {
console.log(item, index);
return !item
})); If I will explicitly replace the empty elements with undefined, then it will return true.
That's the difference between "never assigned a value" and "been assigned the undefined value".
MDN Web Docs
developer.mozilla.org › en-US › docs › Web › JavaScript › Reference › Global_Objects › Array › some
Array.prototype.some() - JavaScript | MDN
1 week ago - The some() method of Array instances returns true if it finds an element in the array that satisfies the provided testing function. Otherwise, it returns false.
W3Schools
w3schools.com › jsref › jsref_some.asp
W3Schools.com
The some() method returns true (and stops) if the function returns true for one of the array elements.
Videos
What does the SOME() array method do? - YouTube
JavaScript Array Methods in Minutes: SOME() — 3 EXAMPLES! - YouTube
14:58
Array some Method in JavaScript | JavaScript Array Methods | ...
02:00
Check If Some Items Pass a Condition - JavaScript Array Some (In ...
00:04
Javascript Array Some Method - YouTube
05:42
JavaScript Array Some Method Practice in 5 Minutes - YouTube
Top answer 1 of 2
8
See MDN:
The some() method executes the callbackFn function once for each element present in the array until it finds the one where callbackFn returns a truthy value (a value that becomes true when converted to a Boolean). If such an element is found, some() immediately returns true. Otherwise, some() returns false. callbackFn is invoked only for indexes of the array with assigned values. It is not invoked for indexes which have been deleted or which have never been assigned values.
You can see that here:
const arr = ['item 1', 'item 2', , 'item 3', , 'item 4', 'item 5'];
console.log(arr.some((item, index) => {
console.log(item, index);
return !item
})); If I will explicitly replace the empty elements with undefined, then it will return true.
That's the difference between "never assigned a value" and "been assigned the undefined value".
2 of 2
0
The elements are actually empty and not undefined
const arr = ['item 1', 'item 2', , 'item 3', , 'item 4', 'item 5'];
// If you see in console, empty element has been filled with undefined
console.log(arr);
VM146:4 (7) ['item 1', 'item 2', empty, 'item 3', empty, 'item 4', 'item 5']
Thats the reason the some script behaves differently. This thread does a good job on explaining stuff
Check the array has empty element or not
GeeksforGeeks
geeksforgeeks.org › javascript › javascript-array-some-method
JavaScript Array some() Method - GeeksforGeeks
July 12, 2024 - The some() method checks if any array elements pass a test provided as a callback function, returning true if any do and false if none do.
Medium
medium.com › poka-techblog › simplify-your-javascript-use-some-and-find-f9fb9826ddfd
Simplify your JavaScript – Use .some() and .find() | by Etienne Talbot | poka-techblog | Medium
September 5, 2019 - This array method helps you determine if one or more of its values correspond to something you’re looking for.
Reddit
reddit.com › r/learnjavascript › what is the correct situation to use array.find() vs. array.includes vs. array.some() ?
What is the correct situation to use array.find() vs. ...
September 14, 2019 -
I understand how each of these methods work, but they all seem to have similar functions to one another, and I'm not sure as to what situation might call for what method.
Top answer 1 of 3
35
const value = arr.find(test) — return the value that passes your test function for when you need to run a test to determine which value you want const bool = arr.some(test) — return true if at least one element passes your test for when you need to see if anything in your array passes your test function const bool = arr.includes(value) — check if a value exists in an array for when you already know the value and you want to check if the array has a copy
2 of 3
1
Use find when you actually need the first element that matches to be returned. Sure you could check to see if the result of find was not undefined and in that way it's similar to some. But sometimes you want the array element returned and sometimes you JUST need to know if it exists. includes is actually pretty different from both of these and is useful for arrays with simple values. Most of the time in production code I deal with arrays of objects and want to pass a function as a truth test to really dig into the contents of the object. If it's a simple array of strings or numbers then sure includes might be all you need.
freeCodeCamp
freecodecamp.org › news › learn-the-every-and-some-array-methods-in-javascript
JavaScript Array Methods – How to Use every() and some() in JS
August 10, 2022 - In JavaScript, every and some help you test if something is true for every element or some elements of an array. In this article, I'll show you how to use these helpful array methods. Table of Contents1How every() and some() Work – an Overview2Param...
Refine
refine.dev › home › blog › tutorials › how to use javascript array some
How to Use JavaScript Array some | Refine
November 4, 2024 - The JavaScript Array.prototype.some method is an iteration method that tests whether any one element in a collection satisfies a given condition. It is commonly used to find items that fulfill involved conditions such as matching the value of ...
4Geeks
4geeks.com › how-to › javascript-array-some-method
How to use the Javascript array some method?
July 16, 2025 - Nowadays known as one of the most familiar Arrays methods to test in Javascript we have the Array Some method. What some() method performs is testing whether at least one element of the array matches the test executed by our custom function.
LinkedIn
linkedin.com › pulse › understanding-distinction-arraysome-vs-arrayfind-shuaibu-muhammad-20j9f
Understanding the Distinction: Array.some() vs. Array.find() ...
February 26, 2024 - Array.some() for Boolean Results: ... Array.some() is your go-to method. It returns a boolean value indicating whether any element passes the test provided by the callback function....
GeeksforGeeks
geeksforgeeks.org › typescript › typescript-array-some-method
TypeScript Array some() Method - GeeksforGeeks
July 12, 2024 - The Array.some() method in TypeScript is used to check if at least one element in the array passes the test implemented by the provided function.
Lucee Documentation
docs.lucee.org › reference › functions › arraysome()
array.some() :: Lucee Documentation
This function calls a given closure/function with every element in a given array and returns true, if one of the closure calls returns true. array.some( closure=function, parallel=boolean, maxThreads=number )
TypeScript
typescriptlang.org › docs › handbook › 2 › everyday-types.html
TypeScript: Documentation - Everyday Types
The type names String, Number, and Boolean (starting with capital letters) are legal, but refer to some special built-in types that will very rarely appear in your code. Always use string, number, or boolean for types. To specify the type of an array like [1, 2, 3], you can use the syntax number[]; ...
Marius Schulz
mariusschulz.com › blog › the-some-and-every-array-methods-in-javascript
The some() and every() Array Methods in JavaScript — Marius Schulz
November 22, 2020 - As soon as every() finds an array element that doesn't match the predicate, it immediately returns false and doesn't iterate over the remaining elements. The predicate function is passed three arguments by both some() and every(): the current array element to test, the index in the array, and the array itself.
Generalist Programmer
generalistprogrammer.com › home › glossary › array.some(): explained [2025]
What is Array.some(): Explained [2025]? Definition & Meaning
November 16, 2025 - The Array.some() method tests whether at least one element in an array passes a provided test function, returning true or false as appropriate. This powerful JavaScript array method executes a callback function once for each element in the array until it finds one where the callback returns ...
Lodash
lodash.com › docs
Lodash Documentation
Creates an array of values by running each element in collection thru iteratee. The iteratee is invoked with three arguments: (value, index|key, collection). Many lodash methods are guarded to work as iteratees for methods like _.every, _.filter, _.map, _.mapValues, _.reject, and _.some.
JavaScript.info
javascript.info › tutorial › the javascript language › data types
Array methods
The function fn is called on each element of the array similar to map. If any/all results are true, returns true, otherwise false. These methods behave sort of like || and && operators: if fn returns a truthy value, arr.some() immediately returns true and stops iterating over the rest of items; if fn returns a falsy value, arr.every() immediately returns false and stops iterating over the rest of items as well.
Edgecompute
js-compute-reference-docs.edgecompute.app › array() › array.prototype.some()
Array.prototype.some() | @fastly/js-compute
The some() method tests whether at least one element in the array passes the test implemented by the provided function. It returns true if, in the array, it finds an element for which the provided function returns true; otherwise it returns false.
LeetCode
leetcode.com › problems › next-greater-element-i
Next Greater Element I - LeetCode
Can you solve this real interview question? Next Greater Element I - The next greater element of some element x in an array is the first greater element that is to the right of x in the same array. You are given two distinct 0-indexed integer arrays nums1 and nums2, where nums1 is a subset of nums2.
Top answer 1 of 3
14
Array.prototype.some() only checks if any element in the array passes test defined in callback function. You should use array find method which returns first element passig test
2 of 3
2
You're looking for Array.prototype.filter instead of Array.prototype.some.
Filter does what you're currently expecting some() to do. some() returns a boolean if 1 or more elements meet your criteria while filter() creates a new array of elements that met your criteria.