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Comment by hrktb | Hacker News Reader

> if (Session["startDate"] + "" == "")

This feels horribly familiar. I'm not sure to recognize the specific language used, but there must be cases where one would like to target empty of filled with non processable characters strings only, and let null and falsy values pass through. This kind of use would typically need a line of comment, but hey...

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I'm guessing you don't realize that the plus operator has less precedence than the == operator.

That if is equivalent to if (startDate + true)

EDIT: I was wrong. I haven't slept.

Sadly you are wrong. See an operator precedence list: http://bmanolov.free.fr/javaoperators.php

You are right, sorry about that.

Does it mean if(1 + 1 == 2) is equivalent to if(1 + true)?

1) + has a higher precedence than ==

2) even if == had a higher precedence, then 1 == 2 would still be false :D

I was wrong, my bad.

Do this in javascript all the time. Adding a `+ ""` forces the object to become a string.

Though not sure why it was required for this particular comparison.

Why not use toString()? It is clearer to the reader that way.

toString() blows up on a null value, the + operator does not.

I've written similar Java code for that reason.

I shell languages I do this a lot.

    if "x$VARIABLE" == "x"

because it handles the cases where $VARIABLE is undefined or multiple words without vomiting all over the place.

I hate when people do that because it's not needed at all. The quoting already fixes everything.

    if [[ "$VARIABLE" == "" ]]

or even better

    if [ -z "$VARIABLE" ]

will handle undefined, empty and multiple words just fine.

Unless you're running with -u, which you should be, in which case it will blow up on an undefined variable. To treat undefined as empty, you want:

    if [[ -z "${VARIABLE:-}" ]]

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