Difference between ++ and +=1 in javascript

Question

Could somebody explain why the following functions give different results. The first does not seem to work, but the second does. I'm puzzled because I thought +=1 and ++ did the same thing.

(I'm not intending to actually use this code, it's just to demonstrate the difference).

/*function 1*/ function incrementIfZero1(base,element) {      if (element == 0) {         return base++;     }     else     {         return base;     } };   /*function 2*/ function incrementIfZero2(base,element) {      if (element == 0) {         return base+=1;     }     else     {         return base;     } };  incrementIfZero1(1,0) /* -> 1*/ incrementIfZero2(1,0) /* -> 2*/ 

Any help is very much appreciated.

Thanks,

Robin

[Edit:]

Thank you for your replies, it makes sense now. I had also tried the following statement, which resulted in the same thing as function 1:

return (base++) 

I'm now surprised that this doesn't give the same result as function 2 - I would have expected the brackets to 'force' it to be evaluated before returning. Any idea why this is not the case?

Answer 1

when you return base++ it returns the value of base just before it gets incremented. You want to do ++base to make sure the increment happens first then it gets returned

otherwise ++ is the same as +=1

[edit] in response to your edit, i tried wrapping random statements in parentheses and most mathematical operators respond as expected, this incrementation seems to be exempt, likely because the syntax of pre-incrementation vs post-incrementation is highly intentional and the statement itself returns a specific value regardless of whether or not you wrap it in parentheses