Question

I have seen in some nodejs scripts variables/objects being used like this:

var myvar1 = myvar2 = myvar3;

Why is this used and what does it mean?

Answer 1

This sets myvar2 to myvar3, and sets myvar1 to myvar2.

I assume myvar3 and myvar2 have been declared before this line. If not, myvar2 would be a global (as there’s no var), and if myvar3 wasn’t defined, this would give an error.

This expands to:

myvar2 = myvar3; // Notice there's no "var" here
var myvar1 = myvar2;