https://github.com/blond/hash-set
:hash: Set with custom equality comparisons
https://github.com/blond/hash-set
built-in-objects equality hash same-value-zero set
Last synced: 17 days ago
JSON representation
:hash: Set with custom equality comparisons
- Host: GitHub
- URL: https://github.com/blond/hash-set
- Owner: blond
- License: mit
- Created: 2016-02-29T22:56:43.000Z (over 9 years ago)
- Default Branch: master
- Last Pushed: 2020-06-01T01:13:25.000Z (about 5 years ago)
- Last Synced: 2025-05-17T02:19:01.380Z (about 1 month ago)
- Topics: built-in-objects, equality, hash, same-value-zero, set
- Language: JavaScript
- Homepage:
- Size: 107 KB
- Stars: 6
- Watchers: 1
- Forks: 2
- Open Issues: 4
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
Awesome Lists containing this project
README
hash-set
========
[![NPM Status][npm-img]][npm]
[![Travis Status][test-img]][travis]
[![Coverage Status][coveralls-img]][coveralls]
[npm]: https://www.npmjs.org/package/hash-set
[npm-img]: https://img.shields.io/npm/v/hash-set.svg
[travis]: https://travis-ci.org/blond/hash-set
[test-img]: https://img.shields.io/travis/blond/hash-set/master.svg?label=tests
[coveralls]: https://coveralls.io/r/blond/hash-set
[coveralls-img]: https://img.shields.io/coveralls/blond/hash-set/master.svg
The original [Set](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set) uses [Same-value-zero](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Equality_comparisons_and_sameness) equality.
Use this package if you need custom comparison behavior.
Install
-------
```
$ npm install --save hash-set
```
Usage
-----
```js
import hashSet from 'hash-set';
// Create Set class which compares objects with JSON.stringify
const JSONSet = hashSet(JSON.stringify);
// Create instance of JSONSet
const mySet = new JSONSet();
mySet.add({ a: 1 });
mySet.add({ b: 2 });
mySet.has({ a: 1 }); // true
mySet.has({ b: 2 }); // true
mySet.has({ c: 3 }); // false, `{ c: 3 }` has not been added to the set
mySet.size; // 2
mySet.delete({ a: 1 }); // removes `{ a: 1 }` from the set
mySet.has({ a: 1 }); // false, `{ a: 1 }` has been removed
mySet.size; // 1
```
API
---
### hashSet(hashFn)
Returns `Set` class with custom equality comparisons.
#### hashFn
Type: `function`
The function to determine the unique of value.
`HashSet` executes a provided function every time you call `add(value)`, `has(value)`, `delete(value)`.
The result of `hashFn(value)` will be used for comparison with the values of `HashSet`. For comparison will be used [Same-value-zero](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Equality_comparisons_and_sameness).
**Example**
```js
const mySet = new Set();
mySet.add(1); // value has been added to the set
mySet.add('1'); // value has been added to the set
// because `Object.is(1, '1')` is `false`
console.log(mySet); // Set { 1, '1' }
```
```js
import hashSet from 'hash-set';
function hashFn(value) {
return value.toString();
}
const StringSet = hashSet(hashFn);
const mySet = new StringSet();
mySet.add(1); // value has been added to the set
mySet.add('1'); // value has not been added to the set
// because `Object.is(hashFn(1), hashFn('1'))` is `true`
console.log(mySet); // Set { 1 }
```
License
-------
MIT © [Andrew Abramov](https://github.com/blond)