jQuery jQuery.isEmptyObject() Method

What You’ll Learn

The jQuery.isEmptyObject() utility returns true when an object has no enumerable properties — the quick way to ask “is this object blank?” This tutorial covers syntax, five worked examples, comparisons with Object.keys(), default-options patterns with $.extend(), and pitfalls beginners should know.

Introduction

Configuration objects, AJAX payloads, and form data often arrive as plain JavaScript objects. Before merging settings or rendering UI, you need to know whether the object actually contains anything — or is just an empty shell like {}.

jQuery provides jQuery.isEmptyObject() (also written $.isEmptyObject()) for exactly that check. It walks enumerable properties with a for...in loop and returns true only when nothing is found — the pattern used throughout jQuery plugin code when applying default options.

Understanding the jQuery.isEmptyObject() Method

jQuery.isEmptyObject(obj) answers: does this object expose any enumerable properties? If the loop finds at least one key, the method returns false. If the loop completes without finding any, it returns true.

This is narrower than “falsy” or “null” checks. An object with properties set to undefined is not empty — the keys still exist. Use isEmptyObject on plain configuration objects, not on arrays, DOM nodes, or null.

📝 Syntax

General form of jQuery.isEmptyObject:

jQuery.isEmptyObject( obj )
// or
$.isEmptyObject( obj )

Parameters

• obj — a plain object to inspect for enumerable properties.

Return value

• true if obj has no enumerable properties.
• false if at least one enumerable property exists.

Minimal workflow

if ($.isEmptyObject(userSettings)) {
  userSettings = { theme: "light", lang: "en" };
}

Examples Gallery

Each example uses $.isEmptyObject(). Open DevTools or use the Try-it links to run them interactively.

console.log($.isEmptyObject({}));              // true
console.log($.isEmptyObject({ name: "John" })); // false

true
false

var empty = {};
var filled = { id: 1 };

console.log($.isEmptyObject(empty));           // true
console.log(Object.keys(empty).length === 0); // true

console.log($.isEmptyObject(filled));           // false
console.log(Object.keys(filled).length === 0);  // false

true
true
false
false

var defaults = { speed: 400, easing: "swing" };

function resolveOptions(userOpts) {
  userOpts = userOpts || {};
  if ($.isEmptyObject(userOpts)) {
    return $.extend({}, defaults);
  }
  return $.extend({}, defaults, userOpts);
}

console.log(resolveOptions({}).speed);        // 400
console.log(resolveOptions({ speed: 200 }).speed); // 200

400
200

var cache = { temp: true, draft: true };

console.log($.isEmptyObject(cache)); // false

delete cache.temp;
delete cache.draft;

console.log($.isEmptyObject(cache)); // true

false
true

function renderProfile(data) {
  if ($.isEmptyObject(data)) {
    return "No profile data";
  }
  return "Hello, " + data.name;
}

console.log(renderProfile({}));                    // "No profile data"
console.log(renderProfile({ name: "Asha" }));     // "Hello, Asha"

No profile data
Hello, Asha

🚀 Common Use Cases

• Plugin defaults — detect blank user options before $.extend.
• Form state — check whether a values object has any fields before submit.
• Cache maps — know when an object store has been fully cleared.
• AJAX guards — skip rendering when JSON parses to {}.
• Feature flags — treat empty config as “all defaults enabled.”
• Legacy jQuery plugins — consistent emptiness checks across browsers.

📝 Notes

• Available since jQuery 1.4.
• Uses for...in — enumerable properties only; non-enumerable keys are ignored.
• Keys with undefined values still make the object non-empty.
• Not designed for arrays, functions, or null — validate type first.
• Pair with $.isPlainObject() when input might not be a plain object.
• Related: $.extend() for merging non-empty options onto defaults.

💡 Best Practices