Why in javascript {} + [] returns 0 while [] + {} returns "[object Object]"?

Question

JavaScript

how to read it?
Thanks :)

Answer 1

At the beginning of the code, JS treats {} as an empty block of code. It {} + [] == +[]'s , and +[] is 0. When the array comes first, {} is added to the empty array, and it's [] + {} = "" + {} = ({}).toString(). An array is a different object because of this:

[].toString() == "";
+[] == 0;
+[x] == x;
+[x,y,z] == NaN; // Ой, это неправильно!
+[x,y,z] != +[x,y,z] // NaN != NaN