数组去重

方法一

function unque(arr) {
      var temp = [];
      for (var i = 0; i < arr.length; i++) {
          if (arr.indexOf(arr[i]) == i) {
              temp.push(arr[i])
          }
      }
      return temp
}
var arr1 = [1, 1, 2, 3, 4, 5, 5, 6, 7, 7]
console.log(unque(arr1))

方法二

function unque1(arr2) {
            var temp1 = [];
            for (var i = 0; i < arr2.length; i++) {


                if (temp1.indexOf(arr2[i]) == -1) {
                    temp1.push(arr2[i])
                }
            }
            return temp1
        }
        var arr3 = [2, 2, 2, 3, 4, 5, 6, 7, 7, 7, 8, 8, 9, 9, 9, ]
        console.log(unque1(arr3))

方法三

 var arr3 = [2, 2, 2, 3, 4, 5, 6, 7, 7, 7, 8, 8, 9, 9, 9, ]
 var item = new Set(arr3)
 var array = Array.from(item)
 console.log('item', array)