Multiple Comparison / Assignment Operators on the Same Line in JavaScript

Question

function test(input){
   var value = input != 1;
}

In the above, what is the line inside of the function doing and how does it work?

Answer 1

See Operator Precedence.

!= has a precedence of 9 and = has a precedence of 17.

Therefore it evaluates input != 1 and then assigns the result to value.

Answer 2

First it's doing the comparison input != 1, and then assigning the result of that (which will be true or false) the variable value. The != is a comparison, the = is an assignment.

This is exactly the same as any other assignment: The right-hand side is evaluated, and assigned to the left-hand side.