关联数组如果从regexp返回，则正在对索引进行排序

Question

I need to save order in array. A normal array was destroying it, so i found associative array, but with indexes from regexp was sorting records too. My function is

var myArray = {};
var searchIndex = '';
$("#searchList").find('li').each(function( index ) {
    id = $( this ).attr('id');
    if(id.match(/search(:?\d+|\w+)/)){
        searchIndex = id.match(/search(\d+|\w+)/)[1]; 
        myArray[searchIndex] = "empty";
    }
});

This code works well, order are saved.

myArray[id] = "empty"; 

http://screenshooter.net/100008827/fhbsvjm But when i want to remove string "search" from id, by regexp, array just sorting indexes...

searchIndex = id.match(/search(\d+|\w+)/)[1]; 
myArray[searchIndex] = "empty";

http://screenshooter.net/100008827/gmxusyu But order should be last->7->9->8

Answer 1

JavaScript does not have associative arrays. The plain objects in JavaScript are similar to associative arrays in some ways, but the order of their properties is not guaranteed.

If you want an associative array that preserves the order of items in the order they were added, it is possible to create one from scratch. Here is a fairly simple implementation that provides that functionality:

 function AssociativeArray() { var items = []; var refs = {}; this.set = function(key, value) { if (key in refs) { refs[key].value = value; } else { var entry = { key: key, value: value }; items.push(entry); refs[key] = entry; } }; this.get = function(key) { var entry = refs[key]; return entry && entry.value; }; this.allItems = function() { return items.slice(); }; } var assoc = new AssociativeArray(); assoc.set(7, "hello"); assoc.set(3, "goodbye"); assoc.set("cheer", "yay"); var items = assoc.allItems(); for (var i = 0; i < items.length; i += 1) { console.log(items[i].key + " - " + items[i].value); } console.log("The item with key 7 is: " + assoc.get(7)); 

The way you would adapt this to your current code is:

var myArray = new AssociativeArray();
$("#searchList").find('li').each(function( index ) {
    var id = $( this ).attr('id'),
        searchIndex;
    if(id.match(/search(:?\d+|\w+)/)){
        searchIndex = id.match(/search(\d+|\w+)/)[1]; 
        myArray.set(searchIndex, "empty");
    }
});

The first code snippet above shows how to iterate through the array in the order that items were added.