return String vs Integer vs undefined vs null

Question

Why does javascript prefers to return a String over any other choices ?

Consider the following snippet.

var arr = [\'Hello1\', \'Hello2\', \         


        

Answer 1

The code a || b is roughly equivalent to a ? a : b, or this slightly more verbose code:

if (a) {
    result = a;
} else {
    result = b;
}

Since || is left-associative the expression a || b || c is evaluated as (a || b) || c.

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So in simple terms this means that the || operator when chained returns the first operand that is "truthy", or else the last element.

This feature can be useful for providing defaults when you have missing values:

var result = f() || g() || defaultValue;

You could read this as: Get the result of f(). If it's a falsey value, then try g(). If that also gives a falsey value, then use defaultValue.