hash-set

The original Set uses Same-value-zero equality.

Use this package if you need custom comparison behavior.

Install

$ npm install --save hash-set

Usage

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.

Example

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' }

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