ExtJS 4 - Cannot read property 'substring' of undefined

Question

I am new to Ext JS 4 and I am currently developing a pretty complex Ext JS MVC application that follows the architecture explained in this (basic) tutorial.

http://docs.sencha.com/extjs/4.0.7/#%21/guide/application_architecture.

Almost all the times I add a new view with the related model, controller and store, as first step I have to fix some mispelled alias or id. It comes to be very tricky since ext does not help me as I would expect, and there is a lot of these ids to look for.

Using Firebug, the error message given to me is:

Uncaught TypeError: Cannot read property 'substring' of undefined localhost:8080/Web/extjs4/ext-debug.js:5246

Is there a way to quickly undestand where the mispelling is?

This is the code portion where the exception is thrown

 parseNamespace: function(namespace) {

            var cache = this.namespaceParseCache,
                parts,
                rewrites,
                root,
                name,
                rewrite, from, to, i, ln;

            if (this.enableNamespaceParseCache) {
                if (cache.hasOwnProperty(namespace)) {
                    return cache[namespace];
                }
            }

            parts = [];
            rewrites = this.namespaceRewrites;
            root = global;
            name = namespace;

            for (i = 0, ln = rewrites.length; i < ln; i++) {
                rewrite = rewrites[i];
                from = rewrite.from;
                to = rewrite.to;
                // 5246 
                if (name === from || name.substring(0, from.length) === from) {
                    name = name.substring(from.length); 

                    if (typeof to != 'string') {
                        root = to;
                    } else {
                        parts = parts.concat(to.split('.'));
                    }

                    break;
                }
            }

            parts.push(root);

            parts = parts.concat(name.split('.'));

            if (this.enableNamespaceParseCache) {
                cache[namespace] = parts;
            }

            return parts;
        },

Thanks in advance.

Answer 1

I sanity check my code with console.log( Ext.getClassName(someObj) ); -- sometimes JSLint can help you find unused variables -- Good Luck!