getJSON响应中自定义jQuery reverse插件失效问题求助

Let's break down why your reverse plugin isn't working and get it sorted out step by step:

1. What's Going Wrong Here? #

Your custom reverse plugin is built for jQuery DOM element collections (like $('li') or $('.item')), not plain JavaScript arrays—which is exactly what your $response from getJSON is. On top of that, you're calling the plugin incorrectly:

• You’re invoking $.fn.reverse() directly from the jQuery prototype, instead of using it on a jQuery instance.
• The plugin’s this context isn’t set to your array, so the loop logic never executes properly (it can’t access this.length for your array).

2. Simple Fixes to Reverse Your JSON Response #

You’ve got a few straightforward options to get the reverse iteration working:

Option 1: Use Native Array Methods (Easiest)

Since $response is a plain JS array, you don’t need a jQuery plugin at all. Use native methods to safely reverse the order without modifying the original array:

// Create a copy of the array, reverse it, then iterate
$response.slice().reverse().forEach(function(v) {
  $("#selector").append('<tr><td>' + v.name + '</td></tr>');
});

• slice() makes a shallow copy of the array so we don’t mess up the original $response.
• reverse() flips the copied array’s order.
• forEach() loops through the reversed array to build your table rows.

Option 2: Update the Plugin to Support Arrays

If you want to keep using a custom reverse utility, tweak it to work with both jQuery collections and plain arrays:

(function ($) { 
  // Utility function for arrays
  $.reverse = function(arr, fn) { 
    var i = arr.length; 
    while(i--) { 
      fn.call(arr[i], i, arr[i]); 
    } 
  };
  // Keep the original plugin for DOM elements (maintains chainability)
  $.fn.reverse = function(fn) { 
    $.reverse(this, fn);
    return this; 
  };
}(jQuery));

Then call it for your JSON array like this:

$.reverse($response, function(k, v) {
  $("#selector").append('<tr><td>' + v.name + '</td></tr>');
});

Option 3: Manual Backward Loop

If you prefer to skip plugins and native methods entirely, just loop backward through the array directly:

var i = $response.length;
while(i--) {
  var v = $response[i];
  $("#selector").append('<tr><td>' + v.name + '</td></tr>');
}

3. Why Your Original Code Failed #

When you wrote $.fn.reverse($response, function(...)), you passed $response as the first argument—but the plugin expects this to be the collection/array it’s operating on. Instead, this was set to the jQuery prototype ($.fn), so this.length was undefined, and the loop never ran.

内容的提问来源于stack exchange，提问作者Jacques