Uncaught (in promise) TypeError: Cannot read properties of undefined (reading ‘displayName’)
If you are encountering the error message “Uncaught (in promise) TypeError: Cannot read properties of undefined (reading ‘displayName’)” while working with TypeScript, don’t worry, you’re not alone. This error typically occurs when you try to access a property of an undefined or null value. In this blog post, we will explore a couple of solutions to help you resolve this issue.
Solution 1: Check for undefined or null values before accessing properties
One way to handle this error is by checking if the object is undefined or null before accessing its properties. You can use the optional chaining operator (?.) to safely access nested properties without throwing an error.
const displayName = obj?.nestedObj?.displayName;
In the code snippet above, we use the optional chaining operator to access the displayName property of the nestedObj object. If any of the objects in the chain are undefined or null, the expression will short-circuit and return undefined.
Solution 2: Use conditional statements to handle undefined or null values
Another approach is to use conditional statements to handle undefined or null values. You can use the if statement to check if the object is defined before accessing its properties.
let displayName;
if (obj && obj.nestedObj) {
displayName = obj.nestedObj.displayName;
}
In the code snippet above, we first check if the obj and obj.nestedObj are defined before assigning the value of displayName. This prevents the error from occurring when accessing properties of undefined objects.
Conclusion
Encountering the “Uncaught (in promise) TypeError: Cannot read properties of undefined (reading ‘displayName’)” error can be frustrating, but with the solutions provided in this blog post, you should be able to resolve the issue. Remember to always check for undefined or null values before accessing properties to avoid such errors.
Leave a Reply