This tip is for those learners who already know what spread & rest operators are but sometimes are unclear when one is being used.

When we see "..." in the code, it is either rest parameters or the spread operator.

There’s an easy way to distinguish between them:

• When ... is at the end of function parameters, it’s “rest parameters” and gathers the rest of the list of arguments into an array. I also like it call it the receiving end.
• When ... occurs in a function call or alike, it’s called a “spread operator” and expands an array into a list.