Pattern: Missing fat arrow
Issue: -
Warns when you use this inside a function that wasn't defined with a fat arrow. This rule does not apply to methods defined in a class, since they have this bound to the class instance (or the class itself, for class methods).
The option is_strict is available for checking bindings of class methods. It is impossible to statically determine whether a function using this will be bound with the correct this value due to language features like Function.prototype.call and Function.prototype.bind, so this rule may produce false positives.