how does if condition evaluates its value in javascript

Question

How does javascript if condition determines its value?, see this example:

<script type="text/javascript">

var bar = ("something" == true);
alert(bar); // 1

if ("something") {
    alert("hey!"); // 2
}

</script>

Why do I get to point //2 while 'bar' at //1 is false?

As I can see bar value gets calculated in almost the same way the if condition, or it doesn't?

Answer 1

"something" == true is false because the string and the boolean have to be coerced into types that can be compared. However, if("something") works because a non-empty string is a truthy value.

Answer 2

It's because of how the javascript type coercion engine works. When you say

"something" == true

javascript calls ToNumber on your "something" string to compare it to the boolean. "something" produce NaN which does not equal true.

However

if("something")

only checks if the string is truthy. Because it's not an empty string, it is in fact truthy.

More here: http://webreflection.blogspot.co.il/2010/10/javascript-coercion-demystified.html