JS array deduplication

One, ES6 array deduplication [...new Set(array)]

var arr = [1,1,3,5,3,4,4,8,7,8];

//method one:

    function unique (arr) { 

         const seen = new Map() 

         return arr.filter( (a) => !seen.has(a) && seen.set(a, 1))

    }

// or method two

function unique (arr) { 

     return Array.from(new Set(arr))  // The Array.from method can convert the Set structure to an array.

}

// or method three

var arr2 = [...new Set(arr)];

Author: You Yuxi
Link: https://www.zhihu.com/question/29558082/answer/44854426
Source: Zhihu
The copyright belongs to the author. For commercial reprints, please contact the author for authorization, and for non-commercial reprints, please indicate the source.