Fix all ESLint rules

[rwu823]

Once #6 PR is merged. we'll get many errors. like this, 😅

So anyone can help to fix it?

cc @cjk-halodule

[rwu823]

Tips: you can run eslint --fix to fix most errors.

[ghost]

我對 unexpected function expression 有點怕怕的。我想等 #8 完成後再來跑比較保險？

[rwu823]

That's OK

[ghost]

Under this project, I've done

$git pull
$npm install -g eslint
$eslint --fix

But it shows $eslint --help
Did I miss anything?

[rwu823]

it is done.