How are arrow functions different from regular functions in JavaScript?

Direct answer

Arrow functions use shorter syntax and capture this lexically; unlike regular functions, they do not have their own this, arguments, or constructor behavior.

Arrow functions are useful for concise callbacks, for example const double = n => n * 2;. Their biggest semantic difference is that they do not create their own this binding.

Arrow functions capture this from the surrounding lexical scope.
They do not have their own arguments object; rest parameters are usually preferred when arguments are needed.
They cannot be called with new as constructors.
Regular functions are usually better when a method needs dynamic this based on how it is called.