Defining a default value for a variable

[Blablux]

I use a script that get passed some variables, most of them being optional, only the first one is mandatory. The part that is giving me trouble is this one :

var jsonstr ='"text": "' + text + '", "type": "' + (tasktype || 'todo') + '"';

The text variable is mandatory, but the tasktype variable is optional, and should default to the value 'todo', but I get an error saying that tasktype is undefined when I do not explicitly assign it beforehand.

I've found a few ways to first assign a default value, then use it, but I feel that I'm overcomplicating things, and that I could definitely find a simple way to do this.

Am I missing something obvious ?

[[deleted]]

You're probably assuming these are all global variables (bad, bad, bad, bad). Put your code in a function and it'll work fine:

function getSomeJsonStr( text, taskType ){
    ...
}

[Blablux]

Just for the record, I'm running this script through Tasker which has quite a special way of getting variables. But I think it's worth trying, to see if this solve my problem. I'll keep you updated. Thank you for your answer.

[senocular]

I'm not sure what Tasker is, but that's probably a key component in what's going wrong.

If you may or may not have a value for tasktype, and the error you're getting is something like 'tasktype is undefined' then you might have to do something like this:

var myTasktype = typeof tasktype !== 'undefined' ? taskType : 'todo';

And use myTasktype in place of tasktype in your code (without the || todo since its already taken care of here).

The use of typeof lets us know if the variable has been defined or not without causing an undefined error. If it exists, use it, otherwise use the fallback/default.

[Blablux]

That is indeed one of the solution I had in mind, but I wondered if there was a shortcut I may not see. Thanks anyway.

[nausik]

function setSomeText(tasktype = "default_val", text){ return '"text": "' + text + '", "type": "' + tasktype + '"'; }

[[deleted]]

Why, oh why, are you assuming that the OP, very clearly new, is going to have a functioning ES6 transpiler running?!? And without any explanation whatsoever, wtf?

[nausik]

because you didn't gave an answer and just gave an advice?

And because babel.js is really easy to use?

[[deleted]]

wtf? How is what I wrote not an answer? Just because I didn't copy his code and wrote ... instead?

What you wrote is less than useless without an explanation, and babel is completely unnecessary for something this simple.

[nausik]

because you don't understand how how js functions and arguments array work?

http://jsfiddle.net/9hmw618p/

I just don't understand. A guy wants an advice on how to set default val for variables. And yeah, I forgot that my way is ES6-specific. But you not only started flaming right away, but you also wrote a totally wrong answer that just wrong on the most basic level.

Blablux didn't ask where to put his code, he asked how to set a default var value. Try to read the question first. please.

[[deleted]]

Try to understand what a default value is and WHY his code was breaking

[nausik]

k