javascript - How to understand sort in array arrangement

Question

        var fruit=[7,10,32,6,9,4];
        document.write(fruit+'<br>');
        fruit.sort(sortFun);
        document.write(fruit);
        function sortFun(ar1,ar2){
            if(ar1>ar2){
                return 1;
            }else if(ar1<ar2){
                return -1;
            }else{
                return 0;
            }
        }

How does this code arrange the array elements? Please give me a detailed explanation. Thank you.

Answer 1

To help you understand, you can try calling the sort method directly:

var fruit=[7,10,32,6,9,4];
fruit.sort();

The return result is: [10, 32, 4, 6, 7, 9]
而不是期待中的：[ 4, 6, 7, 9, 10, 32]

Why is this happening?
Because this is the sort() method on the array prototype chain, which is Array.prototype.sort().

How to study this sort() method in depth:
1. You can go to the mdn document https://developer.mozilla.org...
2. You can go to "Javascript Advanced Programming", but the advanced design is not complete
3. The most violent way is to read the ECMA2015 specifications: http://www.ecma-international...
4. If you really feel it’s a headache, you can read the blog I wrote last year and repeat 1,2 , 3 steps: http://www.jianshu.com/p/b50a...
Hope it can help you...

Answer 2

 fruit.sort(sortFun);

sort 数组的排序方法；
 用法:
        var arr=[]; 
        arr.sort(function(a,b){
            
        })
        比如从小到大：
        var arr=[9,5,6]; 
        arr.sort(function(a,b){
            return a-b;
        })
        
       fruit.sort(sortFun);中的sortFun就相当于arr.sort(function(a,b){})
       中的function(a,b){}；
       if(ar1>ar2){
                return 1;
            }else if(ar1<ar2){
                return -1;
            }else{
                return 0;
            }就相当于return a-b;

Answer 3

You may need this article https://developer.mozilla.org...