uniqBy()

定義

code:ts

export const uniqBy = <T>(arr: T[], predicate: (a: T) => any = a => a): T[] => {

const seen = new Set();

return arr.filter(item => {

const key = predicate(item);

if (!seen.has(key)) {

seen.add(key);

return true;

}

return false;

});

};

code:ts

export const uniqBy = <T>(arr: T[], predicate: (a: T) => any = a => a): T[] => [

...arr

.reduce((map, item) => {

const key = item === null || item === undefined ? item : predicate(item);

map.has(key) || map.set(key, item);

return map;

}, new Map())

.values()

];