freeCodeCamp/curriculum/challenges/english/02-javascript-algorithms-and-data-structures/functional-programming/use-the-every-method-to-check-that-every-element-in-an-array-meets-a-criteria.md
Oliver Eyton-Williams ee1e8abd87
feat(curriculum): restore seed + solution to Chinese (#40683)
* feat(tools): add seed/solution restore script

* chore(curriculum): remove empty sections' markers

* chore(curriculum): add seed + solution to Chinese

* chore: remove old formatter

* fix: update getChallenges

parse translated challenges separately, without reference to the source

* chore(curriculum): add dashedName to English

* chore(curriculum): add dashedName to Chinese

* refactor: remove unused challenge property 'name'

* fix: relax dashedName requirement

* fix: stray tag

Remove stray `pre` tag from challenge file.

Signed-off-by: nhcarrigan <nhcarrigan@gmail.com>

Co-authored-by: nhcarrigan <nhcarrigan@gmail.com>
2021-01-12 19:31:00 -07:00

77 lines
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Markdown

---
id: 587d7dab367417b2b2512b6e
title: Use the every Method to Check that Every Element in an Array Meets a Criteria
challengeType: 1
forumTopicId: 301312
dashedName: use-the-every-method-to-check-that-every-element-in-an-array-meets-a-criteria
---
# --description--
The `every` method works with arrays to check if *every* element passes a particular test. It returns a Boolean value - `true` if all values meet the criteria, `false` if not.
For example, the following code would check if every element in the `numbers` array is less than 10:
```js
var numbers = [1, 5, 8, 0, 10, 11];
numbers.every(function(currentValue) {
return currentValue < 10;
});
// Returns false
```
# --instructions--
Use the `every` method inside the `checkPositive` function to check if every element in `arr` is positive. The function should return a Boolean value.
# --hints--
Your code should use the `every` method.
```js
assert(code.match(/\.every/g));
```
`checkPositive([1, 2, 3, -4, 5])` should return `false`.
```js
assert.isFalse(checkPositive([1, 2, 3, -4, 5]));
```
`checkPositive([1, 2, 3, 4, 5])` should return `true`.
```js
assert.isTrue(checkPositive([1, 2, 3, 4, 5]));
```
`checkPositive([1, -2, 3, -4, 5])` should return `false`.
```js
assert.isFalse(checkPositive([1, -2, 3, -4, 5]));
```
# --seed--
## --seed-contents--
```js
function checkPositive(arr) {
// Only change code below this line
// Only change code above this line
}
checkPositive([1, 2, 3, -4, 5]);
```
# --solutions--
```js
function checkPositive(arr) {
// Only change code below this line
return arr.every(num => num > 0);
// Only change code above this line
}
checkPositive([1, 2, 3, -4, 5]);
```