In a nutshell, the Javascript `every()`

method will take each element from an array and test it against one logical condition. The `every()`

method will return true if ALL the elements from that array satisfy the condition, or false if at least one element fails the condition.

For example, given the following array:

`const arr = [10, 20 , 4, 3, 70]`

The following `every()`

example will return true:

```
let underOneHundred = arr.every((el) => {
return el < 100
})
// underOneHundred is true
```

And given that an arrow function returns by default the last result we can just write:

```
const arr = [10, 20 , 4, 3, 70]
let underOneHundred = arr.every(el => el < 100)
// underOneHundred is true
```

The `every()`

method makes it easy to test if all the elements in an array meet a given condition.

One more example could be:

```
const arr = [1, 3, 5, 2, 7]
let justOddNumbers = arr.every(el => el % 2)
// justOddNumbers is false
```

Alongside the actual element from the array, we can also get access to the index of that element and the full array:

```
const arr = [1]
arr.every( (el, index, a) => {
// el is 1
// index is 0
// a is [1]
})
```

You may also be interested in reading about one of the most underused Javascript array methods: the reduce() method.