Define one-var rule.

[mattcollier]

Enforces one of the basic rules here: https://github.com/digitalbazaar/bedrock/blob/master/CONTRIBUTING.md#javascript

Prefer one variable declaration per line, no elaborate indentation, and declare nearest to where variables are used. You may declare simple iterator vars for loops multiple times in the same function, functional-scope notwithstanding.

With this rule:

let foo, bar;

produces error: Split 'let' declarations into multiple statements.

https://eslint.org/docs/rules/one-var

[mattcollier]

I support this as long as it doesn't break destructuring like this:

const {var1, var2} = foo;
let {var3, var4} = bar;

I've confirmed that it does not impact destructured assignment..