js 배열 중복을 제거하는 세 가지 간단한 솔루션

function removal(arr) { return Array.from(new Set(arr)) } let arr=[1,2,1,3,4,5,5] removal(arr)//[1, 2, 3, 4]

function removal(arr){ return arr.filter((item,index,arr)=>{ return arr.indexOf(item,0) == index; }) } let arr=[1,2,1,3,4,5,5] removal(arr)//[1, 2, 3, 4]

let newArr = arr.reduce((prev, cur) => { prev.indexOf(cur) === -1 && prev.push(cur); return prev; },[]);