Optimize for better minification

[rbrundritt]

I noticed that this library was fairly large. When looking through the source code I noticed there is a lot of room for optimizations that will help with the minification process. A couple of tips:

• If you use the keyword "this" more than 3 times in a function, create a local variable for it and reference that. For example var self = this; The variable will be minified to a single character and save you 3 characters per use of the "this" keyword.
• Create local variables of repeative variable paths to improve minifications but also reduce the variable lookup time. for For example:
  • For this.config cache like var config = self.config; This will save 10 characters per per use.
  • For this.CONSTANTS.STORAGE cache like var = this.CONSTANTS.STORAGE; This will save 19 characters per use.

I'm sure there are some additional optimizations that can be made to help reduce the file size. I wouldn't be surprised if this could the file size could be cut by 30% or more.

[jasonnutter]

@rbrundritt Thanks for the feedback. Given ADAL.js is no longer under active development, we won't be prioritizing enhancements like this. We highly suggest apps to move to MSAL.js: https://www.npmjs.com/package/@azure/msal-browser