toggle

Problem

You have a multi-select list and need to add an item if it's absent or remove it if it's already present — the standard checkbox toggle pattern.

Solution

Use toggle(array, item, selector?, options?) to return a new array with the item added or removed.

import { toggle } from '@vielzeug/arsenal';

toggle(['ts', 'node', 'vue'], 'ts'); // ['node', 'vue']  — removed
toggle(['ts', 'node', 'vue'], 'react'); // ['ts', 'node', 'vue', 'react'] — added

With selector for objects

import { toggle } from '@vielzeug/arsenal';

const tags = [
  { id: 1, name: 'ts' },
  { id: 2, name: 'node' },
];
toggle(tags, { id: 1, name: 'ts' }, (t) => t.id);
// [{ id: 2, name: 'node' }]

Pitfalls

• Without a selector, uses deep equality — pass a selector for object arrays.

Related

• replace
• uniq