// Tutorial //

Using the Array.find Method in JavaScript

Published on September 9, 2020
Default avatar
By Daniel Stout
Developer and author at DigitalOcean.
Using the Array.find Method in JavaScript

While we believe that this content benefits our community, we have not yet thoroughly reviewed it. If you have any suggestions for improvements, please let us know by clicking the “report an issue“ button at the bottom of the tutorial.

The JavaScript Array.find method is a convenient way to find and return the first occurence of an element in an array, under a defined testing function. When you want a single needle from the haystack, reach for find()!

When to Use Array.find

The function and syntax of find() is very much like the Array.filter method, except it only returns a single element. Another difference is when nothing is found, this method returns a value of undefined.

So if you only need a single value, use find()! When you need to find/return multiple values, reach for filter() instead.

How to Use Array.find

Using find() is super easy! The only required parameter of this method is a testing function, and it can be as simple or complex as needed. In its most basic form:

array.find(testingFunction); // that's it!

Simple example:

Here’s a simple example with an array of strings:

const trees = [ 
  "birch", 
  "maple", 
  "oak", 
  "poplar" 
];

const result = trees.find(tree => tree.startsWith("m"));

// "maple"

In non-shorthand, non-ES6 form:

const result = trees.find(function(tree) {
  return tree.startsWith("m");
});

// "maple"

Using with objects:

We can use find() to easily search arrays of objects, too!

const trees = [
  { name: "birch", count: 4 },
  { name: "maple", count: 5 },
  { name: "oak", count: 2 }
];

const result = trees.find(tree => tree.name === "oak");

// { name: "oak", count, 2 }

Using the same example, notice if we use find() when a test has multiple results, we only get the first value found:

const result = trees.find(tree => tree.count > 2);

// { name: "birch", count: 4 }

This is an instance where you should probably use filter() instead. See the difference?

Tip: Separating the testing function

Sometimes you’ll want to re-use the same find() test function in multiple places. In that case, it can be really helpful to create a separate testing function.

Let’s demo this technique, expanding on our previous examples:

const deciduous = [
  { name: "birch", count: 4 },
  { name: "maple", count: 5 },
  { name: "oak", count: 2 }
];

const evergreens = [
  { name: "cedar", count: 2 },
  { name: "fir", count: 6 },
  { name: "pine", count: 3 }
];

// our testing function
const hasFiveOrMore = el => el.count >= 5;

const decResult = deciduous.find(hasFiveOrMore);
// { name: "maple", count: 5 }

const evgResult = evergreens.find(hasFiveOrMore);
// { name: "fir", count: 6 }

Simple, but powerful! 💪

Using the index parameter

Like filter(), there is an optional index parameter we can use. Here’s one last example, using it as part of our testing function:

const evergreens = [
  { name: "cedar", count: 2 },
  { name: "fir", count: 6 },
  { name: "pine", count: 3 }
];

// suppose we need to skip the first element
const result = evergreens.find((tree, i) => {
  if (tree.count > 1 && i !== 0) return true;
});

// { name: "fir", count: 6 }

The index is probably not something you’ll need often — but it’s great to have available at times.

Conclusion

Array.find is a simple but incredibly useful method for searching JavaScript arrays. It’s one of several useful methods available on Arrays, for a more complete guide see How To Use Array Methods in JavaScript: Iteration Methods.

Just remember: only use find when you want a single element returned, and that it returns undefined if nothing is found! Otherwise, use the filter method when you need multiple elements returned.


Want to learn more? Join the DigitalOcean Community!

Join our DigitalOcean community of over a million developers for free! Get help and share knowledge in our Questions & Answers section, find tutorials and tools that will help you grow as a developer and scale your project or business, and subscribe to topics of interest.

Sign up
About the authors
Default avatar
Developer and author at DigitalOcean.

Still looking for an answer?

Was this helpful?
1 Comments

This textbox defaults to using Markdown to format your answer.

You can type !ref in this text area to quickly search our full set of tutorials, documentation & marketplace offerings and insert the link!

Thanks for a good article on clearly explaining this important method.