數(shù)組去重

let arr = [11, 23, 26, 23, 11, 9];
const deduplication = arr => [...new Set(arr)]
console.log(deduplication(arr));  // [ 11, 23, 26, 9 ]

保留數(shù)組中非重復(fù)數(shù)據(jù)

let arr = [11, 23, 26, 23, 11, 9]
const filterNonUnique = arr => arr.filter(i => arr.indexOf(i) === arr.lastIndexOf(i))
console.log(filterNonUnique(arr));  // [ 26, 9 ]

保留數(shù)組中重復(fù)元素

let arr = [11, 23, 26, 23, 11, 9]
const filterUnique = arr => arr.filter(i => arr.indexOf(i) !== arr.lastIndexOf(i))
console.log(filterUnique(arr)); // [ 11, 23, 23, 11 ]

原文鏈接：https://blog.csdn.net/momDIY/article/details/81351140