Reading a non-existent property on an object always returns undefined. Doing so is usually an error; either in the name of the
property or the type of the variable being accessed.
If an attempt is made to access properties of a primitive, the primitive is automatically encased in a primitive-wrapper object for the operation.
But being "promoted" to an object doesn't mean that the primitive will actually have properties to access. The wrapper object still won't have the
non-existent property and undefined will be returned instead.
This rule raises an issue when an attempt is made to access properties of a primitive. Thus this rule should only be activated when you don't use
monkey patching for standard objects, like Number, Boolean and String.
x = 42; y = x.length; // Noncompliant, Number type doesn't have "length" property
The Ember framework introduces a few extensions to String. Since it is a widely used package, the following String
properties will not trigger this rule even though they are not built-in:
camelize capitalize classify dasherize decamelize fmt loc underscore w