[removed] is this a conditional assignment?

Question

From the google analytics tracking code:

var _gaq = _gaq || [];

how does this work?

Is it a conditional variable value assignment? Is i

Answer 1

Actually it's not the same as saying:

if (!_gaq) _gaq = [];

at least not necessarily. Consider this:

function outer() {
  var _gaq = null;
  function inner() {
    var _gaq = _gaq || [];
    // ...
  }

  inner();
  _gaq = 1;
  inner();
}

When there's a "_gaq" (I hate typing that, by the way) in an outer lexical scope, what you end up with is a new variable in the inner scope. The "if" statement differs in that very important way — there would only be one "_gaq" in that case.