Hi Lauri, thank you for this post, I'm just learning JS and this really helped me to understand the spread operator.
As I'm a beginner in JS I have a question: in the "Pass arguments as arrays" part, I understand that x=0, y=1, and z=2. What would happen if my function is expecting 3 parameters but for some reason, the array has 2 or 4 elements? Or we would simply try to make sure that the size of the array and the parameters expected by the function are equal?
Software dev at Netflix | DC techie | Conference speaker | egghead Instructor | TC39 Educators Committee | Girls Who Code Facilitator | Board game geek | @laurieontech on twitter
The name of a function and the number of parameters it takes (the placeholders for arguments) represent something called a function signature. This is unique within the current scope of the program. If you were to pass too many arguments it would throw an error because it would not find a corresponding function signature, i.e. a function with that name taking 2 (or 4) elements.
That may be the case in other languages, but not in JS. In JS, if you pass too many arguments, the extras will be ignored (but accessible through the variable named arguments). If you pass too few arguments, the missing arguments will be given the value undefined (which may result in an error, but not definitely).
Software dev at Netflix | DC techie | Conference speaker | egghead Instructor | TC39 Educators Committee | Girls Who Code Facilitator | Board game geek | @laurieontech on twitter
Hi Lauri, thank you for this post, I'm just learning JS and this really helped me to understand the spread operator.
As I'm a beginner in JS I have a question: in the "Pass arguments as arrays" part, I understand that x=0, y=1, and z=2. What would happen if my function is expecting 3 parameters but for some reason, the array has 2 or 4 elements? Or we would simply try to make sure that the size of the array and the parameters expected by the function are equal?
The name of a function and the number of parameters it takes (the placeholders for arguments) represent something called a function signature. This is unique within the current scope of the program. If you were to pass too many arguments it would throw an error because it would not find a corresponding function signature, i.e. a function with that name taking 2 (or 4) elements.
Got it, thank you!
That may be the case in other languages, but not in JS. In JS, if you pass too many arguments, the extras will be ignored (but accessible through the variable named
arguments). If you pass too few arguments, the missing arguments will be given the valueundefined(which may result in an error, but not definitely).You're correct, I put my Java hat back on and shouldn't have!
Looks like this has some good explanations. stackoverflow.com/questions/126940...