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Last Updated: February 25, 2016
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Custom jQuery Selectors using Expressions

Overview

Below you can find my code snippets. I always wanted to use something more that standard jq and css selectors (:eq, :first, :last, etc). I've learnt how can I do that and now I share it with you. Many people don't use it because they don't know how.

Cheers.

1 - Simple Expression

// standard approach:
$("span[class*=icon]");

// custom selector:
jQuery.extend(jQuery.expr[':'], {
  icon: function(el) {
    var c = el.className.toLowerCase(); 
    return c.match("icon")
  }
});

// much better
$("span:icon");

2 - Expression + as a function

// standard approach:
$("span[class*=icon][class*=mega]");

// custom selector/function:
jQuery.extend(jQuery.expr[':'], {
  icon: function(el, index, meta) {
    var c = el.className.toLowerCase(); 
    return meta[3] ? ( c.match("icon") && c.match(meta[3])) : c.match("icon")
  }
})

// much better
$("span:icon(mega)");

3 - Expression - debug mode

// debug mode:
jQuery.extend(jQuery.expr[':'], {
  debug: function(el, index, meta) {
    console.log("--- debug ---");
    console.log("element: ", el);
    console.log("index: ", index);
    console.log("meta: ", meta);
    console.log("--- /debug ---");
    return el.nodeName.toLowerCase()==="span";
  }
})

$("span:first:debug");
$("span:first:debug(args)");

4. More Examples

// $("a.button.new-repo").attr("data-button", "new-repo");

jQuery.extend(jQuery.expr[':'], {
  button: function(el, index, meta) {
    return el.nodeName.toLowerCase()==="a"&&el.className.match("button")&&el.dataset.button===meta[3];
  }
});

// much better
$("a:button");
$("a:button(new-repo)");
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