js-set-map-lookups

Compare original and translation side by side

🇺🇸

Original

English

🇨🇳

Chinese

Convert arrays to Set/Map for repeated membership checks.

Incorrect (O(n) per check):

typescript

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

Correct (O(1) per check):

typescript

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

将数组转换为Set/Map以进行重复的成员资格检查。

错误示例（每次查找时间复杂度O(n)）：

typescript

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

正确示例（每次查找时间复杂度O(1)）：

typescript

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