数组去重

ES5

var array= [1,5,2,3,4,2,3,1,3,4]

function unique(arr){
    var unique_array = []
    for(var i = 0;i < arr.length; i++){
        if(unique_array.indexOf(arr[i]) == -1){
            unique_array.push(arr[i])
        }
    }
    return unique_array
}

console.log(unique(array)); //[1,5,2,3,4]

ES6

var array= [1,5,2,3,4,2,3,1,3,4]

function unique(array) {
    return [...new Set(array)]
}
console.log(unique(array));//[1,5,2,3,4]