Why does ++[[]][+[]]+[+[]] return the string “10”?

Question

This is valid and returns the string \"10\" in JavaScript (more examples here):

Answer 1

1. Unary plus given string converts to number
2. Increment operator given string converts and increments by 1
3. [] == ''. Empty String

4. +'' or +[] evaluates 0.

   ++[[]][+[]]+[+[]] = 10 
   ++[''][0] + [0] : First part is gives zeroth element of the array which is empty string 
   1+0 
   10