How to solve TypeError: undefined is not an object (evaluating ‘someObject.someProperty’)

The error message “TypeError: undefined is not an object (evaluating ‘someObject.someProperty’)” typically occurs when you try to access a property of an object that is undefined or null.

This error usually happens when you try to access a property or a method of an object that is either null or undefined. For example, if you have a variable called someObject that is supposed to hold an object, but for some reason it is null or undefined, and then you try to do something like someObject.someProperty or someObject.someMethod(), you will get this error.

Here are some steps you can take to solve this error:

1. Check if the object is defined: Make sure that the object you are trying to access exists and is defined. You can do this by logging the object to the console or using the typeof operator to check if it is an object.
2. Check if the property exists: If the object is defined, make sure that the property you are trying to access exists. You can check this by using the “in” operator or by checking if the property is not undefined.
3. Use optional chaining: If you are using modern JavaScript, you can use the optional chaining operator (?.) to access a property of an object that may be undefined or null. This will prevent the error from occurring if the object or property is undefined.
4. Handle the error: If the object or property is undefined and cannot be accessed, you can handle the error by using a try-catch block or by using a default value or fallback value.

Here’s an example of how you can use optional chaining to access a property of an object:

let someObject = {
  someProperty: {
    someValue: 'hello'
  }
};

let value = someObject?.someProperty?.someValue; // uses optional chaining to access the property
console.log(value); // prints 'hello'

If the someProperty property of someObject was undefined, using optional chaining would result in value being undefined, but it would not throw an error.