jQuery jQuery.noop() Method

What You’ll Learn

The jQuery.noop() utility returns a shared empty function — a safe no-op callback when nothing needs to happen. This tutorial covers syntax, plugin default patterns, comparisons with function() {}, and pairing with $.isFunction().

Introduction

Many jQuery APIs expect a function — event handlers, animation callbacks, plugin hooks. But what if the caller does not care about the callback? You could pass null and add if (callback) checks everywhere, or you could pass a function that intentionally does nothing.

jQuery provides jQuery.noop() (also written $.noop — note it is a property holding a function, so you usually write $.noop without parentheses when passing it, or $.noop() which returns the same function). Plugin authors use it as the default for optional callbacks so code can always call callback() safely.

Understanding the jQuery.noop() Method

jQuery.noop is a predefined empty function. Invoking $.noop() or $.noop(any, args) runs no code and returns undefined.

The method takes no parameters when you call $.noop() to retrieve the function. The returned function itself ignores any arguments passed when invoked later.

📝 Syntax

General form of jQuery.noop:

jQuery.noop()
// or — same shared function reference
$.noop

Parameters

• None — jQuery.noop() accepts no arguments.

Return value

• A reference to jQuery’s shared empty function.
• Calling that function returns undefined.

Minimal workflow

var onDone = userCallback || $.noop;
onDone(); // safe even when user omitted callback

Examples Gallery

Each example uses $.noop with jQuery 3.7.1. Open DevTools or use the Try-it links to run them interactively.

var empty = $.noop;

console.log(typeof empty);        // function
console.log(empty());             // undefined
console.log(empty(1, 2, "test")); // undefined — args ignored

function
undefined
undefined

function doWork(userCallback) {
  var callback = userCallback || $.noop;
  // ... perform work ...
  callback("done");
}

doWork();                    // no error — noop runs
doWork(function (msg) {
  console.log(msg);
});                          // logs "done"

(silent when omitted)
done

function myWidget(el, options) {
  var opts = $.extend({}, {
    onInit: $.noop,
    onDestroy: $.noop
  }, options);

  opts.onInit(el);
  return {
    destroy: function () {
      opts.onDestroy(el);
    }
  };
}

myWidget(document.body); // onInit/onDestroy are noop — no crash

(runs without error)

var a = $.noop;
var b = $.noop();
var c = function () {};
var d = function () {};

console.log(a === b); // true — same reference
console.log(c === d); // false — different objects

true
false

// Placeholder until real handler is wired
$("#btn").on("click", $.noop);

// Later replace with real logic — pattern used in some widget lifecycles
console.log($.isFunction($.noop)); // true

true

🚀 Common Use Cases

• Optional plugin callbacks — default when users omit hooks.
• Uniform invocation — always callback() without null checks.
• Animation complete stubs — pass noop when no follow-up action.
• Deferred/promise placeholders — optional done/fail handlers.
• Library internals — jQuery uses noop in its own codebase.
• Testing scaffolding — satisfy function parameters in demos.

📝 Notes

• Available since jQuery 1.4 — still supported in jQuery 3.7.x.
• $.noop and $.noop() refer to the same function.
• Returns undefined when invoked — do not expect a return value.
• Not a replacement for missing logic — use real functions when behavior matters.
• Modern JS may use optional chaining or default params — noop remains idiomatic in jQuery plugins.
• Related: $.isFunction(), $.extend(), Callbacks, Deferred.

💡 Best Practices