Proposed Code Guide Changes

[outofambit]

Hi, here are some thoughts on changes we could make to the code guide to incorporate newer JS features into them. Normally I would open a PR to propose these, but since it is a wiki page, this seemed like the right place to articulate these first.

I read through the code guide and did some perusing through the current set of examples to get a sense of what the general usage and patterns were and would like to propose adding the following to the JavaScript section of the Code Guide:

• Use let and const instead of var
• Use for...of instead of for loops that don't rely on an index for their logic
• Update class syntax to use class fields (as in, replace this.foo; with foo; in class declarations)
• Use static methods and blocks for shared utilities specific to an example.
• Standardize on using a global object when creating new functions and classes. A lot of examples do this but some do not and it is not called out in the code guide. (For example, use const aria = aria || {};)