How to call split(token) on a string that does not contain the token without causing an error?

Question

I have two types of strings as the IDs of elements in my HTML markup:

Dates:

"april-23"
"march-20"

and season names:

"springtime"
"winter"

The dates have a dash separating the month and the day.

The seasons are a single word with no other tokens.

I want to assign the month or the season to a new variable called:

time_of_year

If I do this:

var time_of_year = $(this).attr("id").split('-')[0];

It will work on the months but if I call it on a season name which does not contain the token, will it generate an error?

What's the safe way to do this?

Answer 1

You could check to see if the hyphen character exists using mystring.indexOf('-') (which will return -1 if it doesn't exist). But I'm pretty sure that if you split a string on a character that doesn't contain that character, it will just return the original string.

Answer 2

It doesn't return an error but it does return an array with a length of one.

You could do something like this:

var splitty = $(this).attr('id').split('-');
if (splitty.length > 1) {
   time_of_year = splitty[0];
}
else {
   // do something else magical here
}

Here are the docs on split.

But, if you always want the first value and didn't care about the others, you could just use your original code w/o a problem:

var time_of_year = $(this).attr('id').split('-')[0]

Answer 3

Why don't you add a hyphen prior to performing the split? You are grabbing the first element anyway. What's the difference if it's the first of two or the first of three elements?

var time_of_year = $((this).attr("id")+'-x').split('-')[0];

That way you are grabbing the item to the left of the first hyphen, and there will always be a first hyphen:

"april-23-x" "springtime-x"

(Note, I didn't test this, and am not staking my life on the syntax! But maybe it'll be a fresh idea for you.)

Edit: By the way, I think the example in the Original Post will work anyway. Split should return a list of length 1, and you are grabbing the [0]'th element, which is perfect.

Answer 4

I think what Vorinowsky has is fine.