A short-hand way to do it is to convert it to an array via the ES6 spread operator.
Then all the array functions are available to you.
const mySet = new Set([1,2,3,4]);
[...mySet].reduce(...);
Top answer 1 of 5
267
A short-hand way to do it is to convert it to an array via the ES6 spread operator.
Then all the array functions are available to you.
const mySet = new Set([1,2,3,4]);
[...mySet].reduce(...);
2 of 5
30
To sum up the discussion from comments: while there are no technical reasons for set to not have reduce, it's not currently provided and we can only hope it changes in ES7.
As for map, calling it alone could violate the Set constraint, so its presence here might be debatable.
Consider mapping with a function (a) => 42 - it will change the set's size to 1, and this might or might not be what you wanted.
If you're ok with violating that because e.g. you're going to fold anyway, you can apply the map part on every element just before passing them to reduce, thus accepting that the intermediate collection (which isn't a Set at this point) that's going to be reduced might have duplicated elements. This is essentially equivalent to converting to Array to do processing.
W3Schools
w3schools.com › jsref › jsref_filter.asp
JavaScript Array filter() Method
cssText getPropertyPriority() getPropertyValue() item() length parentRule removeProperty() setProperty() JS Conversion · ❮ Previous JavaScript Array Reference Next ❯ · Return an array of all values in ages[] that are 18 or over: const ages = [32, 33, 16, 40]; const result = ages.filter(checkAdult); function checkAdult(age) { return age >= 18; } Try it Yourself » ·
11:15
How to Use filter() in JavaScript | Filter Arrays Like a Pro - YouTube
JavaScript Array Methods in Minutes: FILTER() — 3 EXAMPLES! - ...
50:21
Map, Filter, Reduce, Set & Map in Javascript | Javascript Full ...
05:58
JavaScript .filter() Method Explained | Easy Guide with Real Examples ...
01:47
JavaScript Basics - How to use the filter method - YouTube
Shaunhartman
shaunhartman.com › articles › using-javascript-sets
Using Sets for Efficient Filtering in JavaScript - Shaun Hartman
We can use this method to add the output to the Set easily. // Only difficulty has been selected const output = currentDifficultySelection .map(difficulty => quizCollection.filter(quiz => quiz.fields.filters.fields.difficulty.includes(difficulty))) .flat(Infinity); output.map(card => filteredQuizCards.add(card)); This works great! Now, let's say we want to combine the filters. For example, we want to filter by both topics and difficulty selection.
AG Grid
ag-grid.com › ag grid › javascript data grid › set filter - overview
JavaScript Grid: Set Filter - Overview | AG Grid
Where the Advanced Filter is enabled, a column that enables a Set Filter also offers is any of and is none of there, reusing the column's own Set Filter configuration and matching the same rows a selection in the Filter List would. filterParams.filterOptions decides for any column: a list naming isAnyOf or isNoneOf offers them on a column with a different filter, and a list leaving them out withholds them here.
DEV Community
dev.to › swarnaliroy94 › understanding-map-filter-set-and-the-spread-operator-in-javascript-49ko
Understanding map(), filter(), Set, and the Spread Operator in JavaScript - DEV Community
September 13, 2025 - The condition given inside the function (num => num % 2 === 0) simply means that only even numbers should be returned. So .filter() will go through each element in the array numbers and return a new array keeping only the even number elements.
Medium
medium.com › @benjamin.flanders96 › how-to-create-a-simple-javascript-filter-67e50b32ccb5
How to Create A Simple JavaScript Filter | Medium
July 22, 2020 - Start by creating an empty <div> ... represent the different categories for your filter. For example, my categories will be fruit, colors, cars, and animals....
GeeksforGeeks
geeksforgeeks.org › how-to-map-reduce-and-filter-a-set-element-using-javascript
How to map, reduce and filter a Set element using JavaScript ? | GeeksforGeeks
February 21, 2023 - To get the difference between two sets in JavaScript, you need to identify elements present in the first set but not in the second. This involves iterating over the first set and filtering out elements that are also found in the second set, ensuring efficient comparison.
MDN Web Docs
developer.mozilla.org › en-US › docs › Web › JavaScript › Reference › Global_Objects › Array › filter
Array.prototype.filter() - JavaScript - MDN Web Docs
September 2, 2026 - The filter() method is generic. It only expects the this value to have a length property and integer-keyed properties. The following example uses filter() to create a filtered array that has all elements with values less than 10 removed.
Built In
builtin.com › software-engineering-perspectives › javascript-filter
How to Filter a JavaScript Array With the Filter() Method | Built In
Assign the new filtered array to a new variable. Here is an example that uses the filter() method to filter an array based on a search criteria for car brands that start with the letter “B.”
Mimo
mimo.org › glossary › javascript › filter
Master JavaScript Filter Operator: Apply Filter Arrays
The filter() method takes a callback function that defines the condition for filtering the array elements. The callback function is called for each element of the array, and elements that return true are kept, while others are excluded. ... Become a full-stack developer. Learn HTML, CSS, JavaScript, and React as well as NodeJS, Express, and SQL
freeCodeCamp
freecodecamp.org › news › javascript-filter-method
How the JavaScript Filter Method Works – Explained with Code Examples
February 15, 2024 - The filter method in JavaScript is designed as a higher-order function that iterates over each element of an array, allowing developers to apply a specific condition to filter out elements.
AG Grid
ag-grid.com › ag grid › javascript data grid › set filter - filter list
JavaScript Grid: Set Filter - Filter List | AG Grid
There is not a one-to-one mapping between Filter List items and rows (as values from multiple rows may map to the same Filter List item), so the Value Formatter for the Filter List will not be passed node or data params, and should just format based on the value. If the data contains Missing Values, the Value Formatter will need to handle how to display the blank values (e.g. return '(Blanks)'). If the data contains complex objects, see Complex Objects for how to use the Value Formatter alongside a Key Creator. The following example shows how Set Filter values are formatted using a Value Formatter.
jQuery
api.jquery.com › filter
.filter() | jQuery API Documentation
This code will alter the first list item only, as it contains exactly one <strong> tag. Within the filter function, this refers to each DOM element in turn. The parameter passed to the function tells us the index of that DOM element within the set matched by the jQuery object.
Medium
medium.com › @edwinlunadlg › creating-a-javascript-filter-a-step-by-step-guide-5f424ac1c507
Creating a JavaScript Filter: A Step-by-Step Guide | by Edwin Luna | Medium
August 9, 2024 - The `filter()` method simplifies the process into a single line, making your code easier to read and maintain. It’s a great example of why higher-order functions (a function that takes another function as an argument or returns a function) are so valuable in JavaScript — they allow you to write more expressive, cleaner code.
Stack Abuse
stackabuse.com › guide-to-javascripts-filter-method
Guide to JavaScript's filter() Method
April 5, 2023 - In this guide, we've taken a look at how JavaScript's filter() method works, and how we can use it to filter out elements from an array, given a predicate/certain filtering criteria. We've taken a look at the accompanying arguments, such as context, index and array that allow you to alter the predicate logic. Finally, we've taken a look at several examples, and covered find() as an alternative for when you're only searching for a single element, and how filter() can be used with other methods in a chain.
DEV Community
dev.to › avinashrepo › 10-example-of-filter-using-in-js-5h6i
10 example of filter using in js - DEV Community
February 6, 2024 - In JavaScript, filtering arrays is a common operation achieved using the filter() method. This method creates a new array with all elements that pass the test implemented by the provided function. Below are five basic examples demonstrating the usage of the filter() method:
CodeConverter
codeconverter.com › articles › javascript-filter
Javascript Filter — Guide with Examples | CodeConverter Blog
February 11, 2026 - If you've ever had to debug a pesky array loop at 2am — only to realize you could've solved the whole thing in one line with `filter()` — then this article's for you. I'm going to share some practical examples of how I use the javascript filter method to simplify my code and reduce debugging headaches.
Alpha Software
documentation.alphasoftware.com › documentation › pages › Ref › Client_Api › A5 › ListBox_class › setFilter Method.xml
setFilter Method - Alpha Anywhere Documentation
The following example shows several ways to set the filter. The filter can be set using regular expressions (RegExp) or a JavaScript function.
BitDegree
bitdegree.org › learn › javascript-filter
JavaScript Filter: Guide on Filtering Arrays and Creating New Ones
February 25, 2020 - Learn how to use JavaScript filter() to apply a test function on arrays. JavaScript filter() applies the test function to all values to create a new array.
freeCodeCamp
freecodecamp.org › news › filter-arrays-in-javascript
How to Filter an Array in JavaScript – JS Filtering for Arrays and Objects
November 7, 2024 - JavaScript's objects are not iterable like arrays or strings (you cannot loop through them). This means you can't use filter(), the for loop method, or any iteration method directly on an object.