Prevent unnamed functions for better debugging

[kumar303]

Unnamed functions make certain types of debugging harder (like profiling). It would be nice to avoid them.

This rule looks like it will enforce named arrow functions: https://github.com/getify/eslint-plugin-proper-arrows

This looks like it will enforced named function functions: https://eslint.org/docs/rules/func-names

I haven't tested either one.

[kumar303]

We will probably want to make some exceptions for things like test definitions: describe(__filename, () => {...})