Javascript methods that can not be called from jqu

问题:

I was reading Learning jQuery 1.3 (Jonathan Chaffer and Karl Swedberg) and while sorting table, they used .get() before calling .sort(), and said

we need to transform jQuery objects into array of DOM nodes. Even though jQuery objects act like arrays in many respects , they don't have any of the native array methods available, such as .sort().

Code:

$("#sort").click(function() {
        var posts = $("#posts_div .post");
        posts.sort(function(a, b) {
           return ($(a).text()) > ($(b).text());
        });       
        $.each(posts, function(index, post) { $("#posts_div").append(post); });
});​

So I tried to do it without using .get(), but surprise it worked even without .get() with latest jQuery, but didn't work with 1.3

So made some fiddles to make it clear

**Not working without .get() jquery 1.2.6 **

Working with .get() jquery 1.2.6

Working without .get() jquery 1.7.2

Working with .get() jquery 1.7.2

So obviously earlier jQuery objects didn't used to have .sort() function same as Javascript arrays? But now they have..

So my question is what are the functions the jQuery objects not support yet, so we can keep in mind to convert to Javascript arrays, before use??

回答1:

jQuery objects currently support 3 array methods:

var methods = 'pop push reverse shift sort splice unshift concat join slice toString indexOf lastIndexOf filter forEach every map some reduce reduceRight'.split(' ')
var implemented = $.grep(methods, function(m) {
    return $.prototype[m] == Array.prototype[m];
});
console.log(implemented); // => ["push", "sort", "splice"]

They also have slice, but it's not the same slice as arrays have:

$.prototype.slice === Array.prototype.slice // => false

回答2:

jQuery does have a .sort method, it just isn't officially documented because it does not follow the usual format of jQuery methods.

The only methods that are supported are the ones listed in the api.

.sort is implemented as:

$.fn.sort = [].sort;

You can add your own additional array methods as needed in the same way.

$.fn.reverse = [].reverse;

If .sort isn't implemented in your version of jQuery, implement it yourself.