Question

I am writing modular javascript code. I wrote a basic calculator with two inputs and four buttons which performs arithmetic operations. When I run my it shows this error in console.

Uncaught ReferenceError: add is not defined

This happens for all buttons. How can I fix this and why it does not work?

Here is my code

Answer 1

You are mixing up variables and object properties. Javascript never implicitly looks up object properties – it’s always a variable lookup with the exception of global object and with-statement.

So specify the object:

    calculation: function(operator) {
        if(operator == 'add')
            return this.add(valone, valtwo);
        else if(operator == 'sub')
            return this.sub(valone, valtwo);
        else if(operator == 'mult')
            return this.mult(valone, valtwo);
        else
            return this.div(valone, valtwo);
    }