The error “cannot read properties of null (reading ‘subtree’)” occurs when you try to access the ‘subtree’ property of a null value. This error usually happens when you try to access a property of an object that is null or undefined.
Here’s an example that demonstrates this error:
let obj = null;
let subtree = obj.subtree; // This line will throw the error
In the above example, ‘obj’ is set to null and you are trying to access its ‘subtree’ property. Since ‘obj’ is null, it does not have any properties and hence accessing ‘subtree’ throws an error.
To solve this error, you need to ensure that the object you are trying to access properties from is not null or undefined. You can use conditional statements or null/undefined checks to handle such scenarios. Here’s an example of how you can handle this error:
let obj = null;
if (obj !== null && typeof obj !== 'undefined') {
let subtree = obj.subtree; // Access property only if obj is not null/undefined
console.log(subtree); // Use the value of subtree here
} else {
console.log("Object is null or undefined");
}
In the above example, you are checking if ‘obj’ is not null and not undefined before accessing its ‘subtree’ property. This ensures that the error is not thrown when the object is null or undefined.