JS sort的排序及使用以及原理

## 一 、升序排列：

var arr=[6,5,4,3,2,1];
            arr.sort(
                function(n1,n2){
                    return n1-n2;
                });
console.log(arr);//[1,2,3,4,5,6]

## 二、降序排列
var arr=[6,5,4,3,2,1];
            arr.sort(
                function(n1,n2){
                    return n2-n1;    //升降序变化位置
                });
console.log(arr);//[1,2,3,4,5,6]

## 三、根据参数属性值排序
var arr = [
    {name:'aaa',age:0},
    {name:'bbb',age:17},
    {name:'ccc',age:9}
];

function compare(property){
    return function(a,b){
        var value1 = a[property];
        var value2 = b[property];
        return value1 - value2;
    }
}
console.log(arr.sort(compare('age'))) //[0,9,17]

## 四、根据参数属性值排序
var arr = [
    {name:'aaa',age:0},
    {name:'bbb',age:17},
    {name:'ccc',age:9}
];

function compare(property){
    return function(a,b){
        var value1 = a[property];
        var value2 = b[property];
        return value1 - value2;
    }
}
console.log(arr.sort(compare('age'))) //[0,9,17]

五、不用sort进行排序

原理和sort排序一样

var arr1= [4,3,2,1]
var arr2 = [1,2,3,4]
//规则1，升序
function rule1 (a,b) {
    return a-b
}
//规则2，倒序
function rule2 (a,b) {
    return b-a
}

//注：方法sortArray 类似sort，可以传递两个参数数组和规则，array，func

function sortArray (array,func){// array 需要排序的数组  func 排序的规则
    var temp;
    for(var i = 0;i<array.length;i++){
        for(var j = 0;j<array.length-1;j++){
            var status = func(array[j],array[j+1])
            if(status>0){
                temp = array[j]
                array[j] = array[j+1]
                array[j+1] = temp
            }
        }
        console.log(array)
    }
    return array
}

//下面是调用
var newarr1 = sortArray(arr1,rule1)
console.log(newarr1)
var newarr2 = sortArray(arr2,rule2)
console.log(newarr2)