JS Set Map Lookups

Use Set and Map for O(1) membership lookups instead of array.includes(). Apply when checking membership repeatedly or performing frequent lookups against a collection. Use when this capability is needed.

tomevault-io bd94fe2 2 files · 1.4 KB Updated

File contents

Use Set/Map for O(1) Lookups

Convert arrays to Set/Map for repeated membership checks.

Incorrect (O(n) per check):

const allowedIds = ['a', 'b', 'c', ...]
items.filter(item => allowedIds.includes(item.id))

Correct (O(1) per check):

const allowedIds = new Set(['a', 'b', 'c', ...])
items.filter(item => allowedIds.has(item.id))

Converted and distributed by TomeVault — claim your Tome and manage your conversions.

tomevault-io/skills-registry/tree/main/theorcdev--8bitcn-ui--js-set-map-lookups commit bd94fe2c15

Frequently asked questions

npx skillmds@latest add tomevault-io/js-set-map-lookups