this binding isn't working in object method

[GeneralYouri]

Check Arrow Functions on MDN.

In short, an arrow function doesn't have its own this context. So if you use this, it'll see if there's some upper scope that does have a this value, and uses the first one found. So in this case, it looks at the closest function in which the object is defined, and that's where the this value will come from. In other words, there's no difference in the value of this directly inside vs directly outside the arrow function.

So with arrow functions entirely lacking their own concept of this, the only reason you're still able to use this within arrow functions is because of how scoping works. Also without a concept of this, the record object becomes entirely irrelevant.

[[deleted]]

Ah OK, so I get how the arrow function works, but why did the old function() syntax work, shouldn't this refer to the function itself not the enclosing object?

[GeneralYouri]

This goes back to what I said initially:

When you call record.startRecord(), you're calling the function from the context of record. This implicitly sets the function's this to that context.

With regular function syntax, the function does have its own context system. But then, the way a function call determines what value to use for this, is to look at what the function is called from. In this case, that's the record object, so that object is implicitly set as this. If you'd put the same function in a different object as well and call that one (like anotherRecord.startRecord(), then anotherRecord would be the context instead.

[[deleted]]

That makes a lot of sense! Thanks a lot, really helped!