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Chris Bongers
Chris Bongers

Posted on • Originally published at

JavaScript every() method

Yesterday we had a look at the JavaScript some() method, and today we will focus on its brother every().

The main difference between the two:

  • some(): If at least one matches
  • every(): All must match!

Both of them will give us a boolean value back.

Using the Javascript every() method

Let's start by creating an array of items.

const items = [
  { name: 'T-shirt plain', price: 9 },
  { name: 'T-shirt print', price: 20 },
  { name: 'Jeans', price: 30 },
  { name: 'Cap', price: 5 }
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Let's say we want to check if all the items have a name.

const haveNames = items.every(item => {

// Returns true
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If we now remove the name on our item, it will return false.

Let's take a more accurate example.
We have a list of users, with temperatures, we want to see if everyone is under 37.8, else someone potentially has a risk of Covid-19.

const users = [
  { name: 'Bob', temperature: 36.3 },
  { name: 'Sarah', temperature: 37.9 },
  { name: 'Billy', temperature: 36.9 },

const temperature = users.every(user => {
  return user.temperature < 37.8;

// Returns false
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Whoops! Sarah has a high temperature, so now we get a false back, this means we need to do something.

I hope this shows how one line can beat an array to loop over people.

The syntax for every is as follows:

const new = original.every(function(value));
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Inside our function, we can check on certain properties the value has.

And remember:

Stay safe

Thank you for reading, and let's connect!

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Top comments (2)

mutale85 profile image

Never knew about these method. Thanks for sharing.
We can follow each other on twitter.

dailydevtips1 profile image
Chris Bongers

Hey, glad you like them! ✌️