数组的合并

语法:
arrayObject.concat(arrayX,arrayX,.........arrayX)
arrayX: 必需,该参数可以是具体的值,一可以是数组对象,可以是多个
返回值: 返回一个新数组,该数组时通过把所有arrayxX 参数添加到 arrayObject中生成的,如果要进行 concat()操作的参数是数组,那么添加的是数组的元素,而不是数组
     var a = [1,2,3,4,5]
    var b = [‘a‘,‘b‘,‘c‘,‘d‘,‘e‘]
    var c = a.concat(b) 
结果: (10)?[1,5,"a","b","c","d","e"]

let arr1 = [1,1,6,9,4]
    let arr2 = [1,7,8,8]
    function uniqueArr(arr1,arr2) {
        //合并两个数组
        arr1.push(...arr2)//或者arr1 = [...arr1,...arr2]
        //去重
        let arr3 = Array.from(new Set(arr1))//let arr3 = [...new Set(arr1)]
        console.log(arr3) 
    }

   uniqueArr(arr1,arr2)

var arr1 = [1,4]
    var arr2 = [1,arr2){
        var arr3 = arr1.concat(arr2)
        var arr4 = []
        for(var i=0,len=arr3.length; i<len; i++) {
            if(arr4.indexOf(arr3[i]) === -1) {
                arr4.push(arr3[i])
            }
        }
        console.log(arr4)
    } 
    uniqueArr(arr1,arr2)