Update allUnique.md

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Isabelle Viktoria Maciohsek
2020-10-19 22:17:39 +03:00
committed by GitHub
parent ba33e9e1de
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@ -3,17 +3,16 @@ title: allUnique
tags: array,beginner
---
Checks if all elements in an array are equal and returns`true` else returns `false`.
Checks if all elements in an array are unique.
- Use `Array.prototype.length` property to return the number of elements in that array.
- Use `Set()` object to collect unique elements from the given array and then the `Set.prototype.size` to get the number of elements in the set
- Check the two values for equality
- Create a new `Set` from the mapped values to keep only unique occurences.
- Use `Array.prototype.length` and `Set.prototype.size` to compare the length of the unique values to the original array.
```js
const allUnique = myArray => myArray.length === new Set(myArray).size;
const allUnique = arr => arr.length === new Set(arr).size;
```
```js
allUnique([1,2,3,4,5]); // true
allUnique([1,1,2,3,4]); // false
allUnique([1, 2, 3, 4]); // true
allUnique([1, 1, 2, 3]); // false
```