数组去重

//数组去重----------自定义去重函数
        const uniq = (arr) => {
            let map = new Map()
            for (let i = 0; i < arr.length; i++) {
                let value = arr[i]
                if (value === undefined) {
                    continue
                }
                if (map.has(value)) {
                    continue
                }
                map.set(value, true)
            }
            return [...map.keys()]
        }
        let arr = [1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 3, 6, 5, 4, 7, 8, 9]
        let arrUniq = uniq(arr)
        console.log(arrUniq)//[1, 2, 3, 6, 5, 4, 7, 8, 9]

//数组去重----------Set
        let arr = [1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 3, 6, 5, 4, 7, 8, 9]
        let setArr = [...new Set(arr)]
        console.log(setArr)//[1, 2, 3, 6, 5, 4, 7, 8, 9]