27 lines
745 B
Markdown
27 lines
745 B
Markdown
---
|
|
title: Subset of iterable
|
|
tags: array
|
|
expertise: intermediate
|
|
author: maciv
|
|
cover: blog_images/last-light.jpg
|
|
firstSeen: 2020-10-11T11:53:08+03:00
|
|
lastUpdated: 2020-10-22T20:24:30+03:00
|
|
---
|
|
|
|
Checks if the first iterable is a subset of the second one, excluding duplicate values.
|
|
|
|
- Use the `Set` constructor to create a new `Set` object from each iterable.
|
|
- Use `Array.prototype.every()` and `Set.prototype.has()` to check that each value in the first iterable is contained in the second one.
|
|
|
|
```js
|
|
const subSet = (a, b) => {
|
|
const sA = new Set(a), sB = new Set(b);
|
|
return [...sA].every(v => sB.has(v));
|
|
};
|
|
```
|
|
|
|
```js
|
|
subSet(new Set([1, 2]), new Set([1, 2, 3, 4])); // true
|
|
subSet(new Set([1, 5]), new Set([1, 2, 3, 4])); // false
|
|
```
|