In its current version, JavaScript is an interpreted programming language developed from the concept of prototypes. This language is widely used for web pages as well as server-side.

When you try to complete your task, you get this error: “Uncaught TypeError: Cannot destructure property usrname of ‘undefined’ or ‘null’ in Javascript“.

This error is one of the most popular errors any programmer will make. So, why does it appear, and how can it be resolved? We’ll go over it with you.

Why Does The Error ”Uncaught TypeError: Cannot destructure property usrname of ‘undefined’ or ‘null’ in Javascript” Occur?

You face this error when you are running one code like this.

function testFn({usrname= 'empty'}={}) {
  console.log(usrname);
}

testFn(null);

And the above error may occur like this.

Uncaught TypeError: Cannot destructure property name of 'undefined' or 'null'. at test (:1:15) at :1:1

You have encountered the error ”Uncaught TypeError: Cannot destructure property usrname of ‘undefined’ or ‘null’ in Javascript” because you are attempting to destructure property from a value that is undefined.

The Effective Methods For ”Uncaught TypeError: Cannot destructure property usrname of ‘undefined’ or ‘null’ in Javascript” Error

Solution 1: Destructure in the first line of the function

If null is passed, the default parameter will not be assigned.

function testFn(arg = 'foo') {
  console.log(arg);
}

testFn(null);

Instead, destructure in the first line of the function:

function testFn(arg) {
  const { name = 'empty' } = arg || {};
  console.log(name)
}

testFn(null);

Solution 2: Default arg to in the function params function test 

Instead of const usrname = ’empty’ = arg || ;, you can default arg to in the function params function test (arg =), and then remove the || from the destructuring statement const usrname = ’empty’ = arg; you personally find this easier to read and a bit cleaner.

Solution 3: Pass an object empty by omitting the parentheses

It is recommended to pass an object empty by omitting the parentheses if you don’t have any arguments or a value given to it but wish to pass it because you intend to assign one later.

Let’s assume you have:

The following function :

const {signup} = useAuth()

Because you are simply giving the object without any parameters, this will undoubtedly result in an error. In order to correct this, remove the empty object from the parenthesis as seen below:

const signup = useAuth()

Then apply it to your subsequent function or class as below:

async {
     ....
     await signup(emailRef.current.value, passwordRef.current.value)
     ...
}

After doing that, your error will be resolved and your program will run well without any errors. Let’s try it to get your desired results.

Conclusion

JavaScript can be learned quickly and is easily applied for various purposes, from improving website functionality to running games and creating web-based software.

Furthermore, there are thousands of JavaScript and application templates out there, thanks to the dedication of the community, especially Github.

The solutions mentioned above are the best options for those still confused with this error: “Uncaught TypeError: Cannot destructure property usrname of ‘undefined’ or ‘null’ in Javascript“.

Read more

→ Tips On Solving The Error “Uncaught TypeError: Cannot read property ‘ContentContainer’ of undefined”