### **1.原生封裝函數** ~~~ var a = [1, 2, 3, 4, 5, 1, 2, 4] function duplicateRemoval(arr) { var newArr = [] var temp = 0; for (var i = 1; i < a.length; i++) { for (var j = 0; j < i; j++) { if (arr[i] == arr[j]) { temp = temp + 1 } if (temp == 0) { newArr[0] = arr[0] newArr[i] = arr[i] } } } return newArr } console.log(duplicateRemoval(a)); ~~~ #### **2.內置對象 includes:** ~~~ var a = [11,11,22,44,33,33]; var temp = []; a.forEach(element =>{ if(!temp.includes(element)){ temp.push(element) } }) console.log(temp); ~~~ #### **3.es6新加方法：** ~~~ var a = [11,11,22,44,33,33]; console.log([...new Set(a)]) ~~~