New Object In Constructor From Class Undefined

I'm creating a new object from a class in a constructor, and whenever it runs I get an error that operate is undefined in the method, though it is defined in the constructor. Opera

Solution 1:

Change from this:

router.post("/", controller.update)

to this:

router.post("/", controller.update.bind(controller))

When you pass controller.update it only passed a pointer to the method and any association with the controller object is lost. Then, when that update method is called later, there is no association with the appropriate object and thus the this handler in the method is wrong and you get the error you were seeing.

You either force the binding of the update method within the object or when you pass the method elsewhere that might not be called correctly, you can use the above structure to pass a bound version of the method.

You could also modify your definition of the update method to permanently bind it to your object in the constructor by adding this to the constructor:

this.update = this.update.bind(this);