Introduction to the Error: “Uncaught TypeError: $(…).find is not a function”
In jQuery, the .find() method is commonly used to search for elements inside a given DOM element. The error “Uncaught TypeError: $(…).find is not a function” usually occurs when you try to call the .find() method on an object that is not a jQuery object, or when the object you’re working with does not have the method you are attempting to use.
This error arises because the .find() method is specific to jQuery objects, and if you are working with a plain JavaScript object, a DOM element, or something that is not a jQuery object, the .find() method won’t be available, thus resulting in this TypeError.
In this detailed guide, we will explore how this error occurs, the different causes, and step-by-step solutions to resolve it.
1. Understanding the “Uncaught TypeError: $(…).find is not a function” Error
To break this error down:
$(...)is shorthand for the jQuery function, which returns a jQuery object that provides jQuery methods (like.find(),.addClass(),.css(), etc.).- The
.find()method is used to search for descendant elements within the selected elements. - When you try to call
.find()on an object that is not a jQuery object, JavaScript throws the “Uncaught TypeError: $(…).find is not a function” error.
Example:
let myElement = $('#myDiv');
myElement.find('.child'); // This works because myElement is a jQuery object
However, if myElement is a non-jQuery object (such as a native DOM element or an undefined value), calling .find() will result in the error.
2. Common Causes of the “Uncaught TypeError”
2.1 Working with Non-jQuery Objects
One of the most common causes of this error is trying to use .find() on something that is not a jQuery object. For example, if you are using document.getElementById(), document.querySelector(), or similar methods, they return native DOM elements, not jQuery objects, and therefore do not have jQuery methods like .find().
Example:
var myElement = document.getElementById('myDiv'); // Native DOM element
myElement.find('.child'); // Throws error: find is not a function
In the example above, myElement is a native DOM element, which does not have the .find() method.
2.2 jQuery is Not Loaded Properly
Another possible cause is that jQuery might not be loaded properly or at all. If jQuery is not available, the $ (or jQuery) function will not be defined, causing errors when trying to call jQuery methods such as .find().
You can confirm that jQuery is loaded by checking the browser’s developer console. If jQuery is missing, you will see an error like Uncaught ReferenceError: $ is not defined.
2.3 Conflicting Versions of jQuery
If you’re using multiple versions of jQuery on the same page, there may be conflicts, especially if one of the versions does not fully support certain jQuery methods.
2.4 Undefined Variables
The error can also occur if you are trying to call .find() on an undefined or null variable.
Example:
var myElement;
myElement.find('.child'); // Throws error: Cannot read property 'find' of undefined
In this case, myElement is undefined, and you are trying to call .find() on it, which results in the error.
3. Diagnosing and Fixing the Error
3.1 Ensure You Are Using jQuery Objects
If you’re using jQuery methods like .find(), make sure that the object you are working with is a jQuery object. You can convert native DOM elements to jQuery objects by wrapping them in $().
Solution Example:
var myElement = $('#myDiv'); // jQuery object
myElement.find('.child'); // No error, works as expected
Alternatively, if you’re working with a native DOM element (for example, from document.getElementById()), you can wrap it in $() to convert it into a jQuery object.
Fixing Non-jQuery Object:
var myElement = document.getElementById('myDiv'); // Native DOM element
$(myElement).find('.child'); // Now it's a jQuery object, so .find() works
This ensures that you are working with a jQuery object, which allows you to use the .find() method.
3.2 Verify jQuery Is Properly Loaded
If jQuery is not loaded or loaded incorrectly, you will need to ensure that it is included in your project. This can be done by adding a <script> tag to include jQuery either from a CDN or locally.
Fixing Missing jQuery:
<!-- Include jQuery from a CDN -->
<script src="https://code.jquery.com/jquery-3.6.0.min.js"></script>
<script>
$(document).ready(function() {
$('#myDiv').find('.child');
});
</script>
Make sure the <script> tag that loads jQuery appears before your custom JavaScript code, to ensure jQuery is available when you use it.
3.3 Handle Undefined or Null Values
If the variable is undefined or null, attempting to call .find() will throw an error. Always check whether the element exists before calling methods on it.
Solution Example:
var myElement = $('#myDiv');
if (myElement.length) {
myElement.find('.child'); // Safe to call .find() since the element exists
} else {
console.log('Element not found');
}
In this solution, the myElement.length check ensures that the element exists and is not null or undefined before attempting to call .find().
3.4 Check for DOM Element Wrapping in jQuery
In some cases, you might be working with a collection of DOM elements, which are not automatically converted to jQuery objects. To resolve this, wrap the collection in $() before using jQuery methods.
Fixing Non-jQuery DOM Collection:
var elements = document.querySelectorAll('.parent'); // NodeList of DOM elements
$(elements).find('.child'); // Wrap it in $() to make it a jQuery object
Here, document.querySelectorAll() returns a NodeList, which is not a jQuery object. By wrapping it with $(), we convert it into a jQuery object, enabling the use of .find().
4. Additional Considerations
4.1 Chaining with jQuery
One of the features of jQuery is chaining, which allows multiple methods to be executed on a jQuery object in a single line. Ensure that when you’re chaining, the object you start with is a valid jQuery object.
Example of Chaining:
$('#myDiv').find('.child').css('color', 'red').show();
Here, .find() will work correctly if $('#myDiv') is a jQuery object.
4.2 Avoiding Common Mistakes
- Using native DOM methods without jQuery: If you’re using jQuery, always prefer using jQuery methods like
.find()and.each()instead of their native counterparts. - Mixing jQuery and vanilla JavaScript: Sometimes, mixing jQuery and vanilla JavaScript can cause issues. Stick to jQuery for DOM manipulation or convert vanilla JavaScript elements to jQuery objects as needed.
4.3 Handling Multiple jQuery Versions
If you’re using multiple versions of jQuery, ensure that the correct version is loaded and there are no conflicts. You can use jQuery.noConflict() to resolve conflicts between multiple versions.
Example:
var $jq = jQuery.noConflict(); // Use $jq instead of $
$jq('#myDiv').find('.child'); // Use $jq to call jQuery methods
5. Conclusion
The error “Uncaught TypeError: $(…).find is not a function” is a common issue that occurs when trying to use the .find() method on non-jQuery objects, such as native DOM elements, undefined values, or non-jQuery collections. To resolve this error, ensure that:
- You are working with jQuery objects (use
$()to wrap native DOM elements). - jQuery is properly loaded in your project.
- You handle null or undefined values before using jQuery methods.
- You ensure compatibility when mixing jQuery and vanilla JavaScript.
By following the troubleshooting steps outlined in this guide, you can prevent and resolve this error, allowing you to use jQuery’s .find() method effectively in your web development projects.