Web Blockly Style Guide needs updating for ES6

[cpcallen]

Where

Web Blockly Style Guide, "Don't" section

What

• Text
• Image or Gif
• Other

Old content

TL;DR

Follow the Google JavaScript style guide. If you are not sure which style to use, follow the style of the existing code. If the style guide says to use a feature that does not exist in Internet Explorer 10, ignore it.

Do

• Redeclare variables in for loops. That is, always write for (var i = 0; ...) instead of for (i = 0; ...).

Don't

• Use ES6.
  • It isn't implemented on all of the platforms that we support.
• Use let (compatibility table).
• Use const (compatibility table).

Suggested content

TL;DR

Update with instructions to clarify we are using ES6:

Follow the Google JavaScript style guide. New code should use ES6 language features like let, const, class, destructuring assignment, etc. where applicable.

I suggest following this with a new section:

Migration to ES6 and updated style guide

Blockly was was originally written in ES5.1 in compliance with an older, then-current version of the Google JavaScript Styleguide. We are migrating the codebase to ES6 and the new style guide. Older browsers, including Internet Explorer 10, will continue to be supported by transpilation to ES5.1 using the Closure Compiler.

When modifying existing code be consistent with whichever style is in use, but when writing new code ensure it complies with the new style guide, including using most ES6 features where applicable.

Do

Change var to let:

• Redeclare variables in for loops. That is, always write for (let i = 0; ...) instead of for (i = 0; ...).

Don't

• Remove mentioned items from this section.

Additional context

See #5026.

[cpcallen]

(Updated description above with a change to the Do section.)