Did you define the function with arrow function?

write console.log(this) on the 1st valid line above arrow function. 
The value of this in the arrow function will be equal to that console log

Did you call 'bind' 'call' 'apply' on the function when you invoked it?

this equals to the 1st argument of 'bind' 'call' 'apply'

All other cases

this equals to whatever is to the left of . in the method call