reconsider the defaults of eslint config

things has changed since eslint was created in 2013. It is time to reconsider the defaults of eslint config. I would suggest the changes:

1. sourceType: “script” => “module”

• native esm has been supported by latest modern browsers and node.js
• a large number of devs are writing esm, and using something like babel/ts to support older browser/node.js versions.

1. ecmaVersion: 5 => “latest” we have often got issues like “unexpected token…” just because not config ecmaVersion. e.g. https://github.com/eslint/eslint/issues/11643 the change should be good for users & maintainers.

2. –ext: “.js” => “.js,.mjs,.cjs”

it is a breaking change, but it’s very easy to restore the old behaviour

{
  "parserOptions": {"ecmaVersion": 5, "sourceType": "script",}
}

if we agreed to the change, document & eslint --init should be updated to reflect the change, too.

[nzakas]

I’ll handle this as I’m working on the new config.

[nzakas]

Fixed in #15185