Javascript apply .join() to item in object collection only if not undefined/empty/null?

Question

In Javascript I have a collection of objects, whose values I'm storing in variable

var filters = {
    BeginDate: $("#BeginDateRange").val(),
    EndDate: $("#EndDateRange").val(),
    ListOfCodes: $("#ListOfCodes").val(),
    //ListOfCodes: $("#ListOfCodes").val().join(),
    ...
}

Based on where I use the collection, some of its objects remain 'undefined', and it is intended.

ListOfCodes above is an array of string values, and I want to pass it to the binder as a single comma-separated string (e.g ["1"], ["2"] -> "1,2")

I was able to make a use of .join(), and it worked successfully. However, I found later that the code will crash if the .join() does not have a value to join.

Is there a way to apply .join() INSIDE the collection to the variable ONLY if it has value? Something like

var filters = {
    BeginDate: $("#BeginDateRange").val(),
    EndDate: $("#EndDateRange").val(),
    ListOfCodes: if( $("#ListOfCodes").val() )
                     {$("#ListOfCodes").val().join()} 
                  else
                      {$("#ListOfCodes").val()}    //value remains undefined
    ,
    ...
}

EDIT: I ask about the possibility of applying .join() method inside the collection, not checking for empty values.

Possible duplicate of [Remove empty elements from an array in Javascript](https://stackoverflow.com/questions/281264/remove-empty-elements-from-an-array-in-javascript) — Dexygen, Dec 22 '17 at 20:47
Assign to variables then test with an if statement? `if (variable == null){ // your code here. }` — Iskandar Reza, Dec 22 '17 at 20:48
@I.R.R. My question is if I can do it INSIDE the collection. — Vadzim Savenok, Dec 22 '17 at 20:49
@Cruiser I'm testing your suggestion for both cases, I'll let you know once I get the results. — Vadzim Savenok, Dec 22 '17 at 20:55
it's possible you won't be able to call join() after .val(), however. it's just a suggestion on how you can test for a value or assign it to undefined — Cruiser, Dec 22 '17 at 20:56
@Cruiser It didn't work, unable to get property join of undefined or null reference. — Vadzim Savenok, Dec 22 '17 at 20:58
is there a reason you can't just test the var before you use join() on it? — Cruiser, Dec 22 '17 at 20:58
What about a ternary statement? `ListOfCodes: ($("#ListOfCodes").val()) ? $("#ListOfCodes").val().join() : null` — ReyHaynes, Dec 22 '17 at 20:59
@ReyHaynes If you want some free points, write it as an answer, and I'll accept it. — Vadzim Savenok, Dec 22 '17 at 21:03
@ReyHaynes even easier if you just do something like `ListOfCodes: ($("#ListOfCodes").val() || "").join()`, so you get an empty string as default. — VLAZ, Dec 22 '17 at 21:03
@Herohtar You're right, sorry. I was just in a hurry, and made a mistake. My main point was to use `||` instead of terniary as it's shorter and you can get a default value. — VLAZ, Dec 22 '17 at 22:42

score 2 · Accepted Answer · answered Dec 22 '17 at 21:06

2

Just moving this as an answer.

What about a ternary statement?

ListOfCodes: ($("#ListOfCodes").val()) ? $("#ListOfCodes").val().join() : null

answered Dec 22 '17 at 21:06

ReyHaynes

2,932
1
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Accepted. Thanks a lot! – Vadzim Savenok Dec 22 '17 at 21:07

Javascript apply .join() to item in object collection only if not undefined/empty/null?

1 Answers1