Like a Set, but provides the index of the key in the backing array

This is designed to allow synchronizing a second array with the contents of the backing array, like how in a sourcemap sourcesContent[i] is the source content associated with source[i], and there are never duplicates.


npm install @jridgewell/set-array


import { SetArray, get, put, pop } from '@jridgewell/set-array';

const sa = new SetArray();

let index = put(sa, 'first');
assert.strictEqual(index, 0);

index = put(sa, 'second');
assert.strictEqual(index, 1);

assert.deepEqual(sa.array, [ 'first', 'second' ]);

index = get(sa, 'first');
assert.strictEqual(index, 0);

index = get(sa, 'second');
assert.strictEqual(index, undefined);
assert.deepEqual(sa.array, [ 'first' ]);