Question

I was playing around with some variables today to get a better feel for them and I came across something that looks peculiar to me. Here’s an example in JavaScript

var foo = "Sethen";
var bar = foo;
var bar = "Sethen is " + bar;
console.log(bar);

We get the output of Sethen is Sethen which is not what I would expect. What I am seeing is an assignment to bar and then another assignment to bar that overwrites the bar value. I would expect to see instead Sethen is Sethen is. This also happens in PHP. Is there something fundamental I am missing here?

Why does this work as Sethen is Sethen when bar is getting assigned twice??

Answer 1

bar is assigned after computing the right-hand side expression.

Most assignment operators in a lot of languages have a very low precedence when it comes to order of operations.

Mozilla has a whole document on the operator precedence of JavaScript.