Javascript – Join strings with a delimiter only if strings are not null or empty

javascriptstring

This feels like it should be simple, so sorry if I'm missing something here, but I'm trying to find a simple way to concatenate only non-null or non-empty strings.

I have several distinct address fields:

var address;
var city;
var state;
var zip;

The values for these get set based on some form fields in the page and some other js code.

I want to output the full address in a div, delimited by comma + space, so something like this:

$("#addressDiv").append(address + ", " + city + ", " + state + ", " + zip);

Problem is, one or all of these fields could be null/empty.

Is there any simple way to join all of the non-empty fields in this group of fields, without doing a check of the length of each individually before adding it to the string?

Best Answer

Consider

var address = "foo";
var city;
var state = "bar";
var zip;

text = [address, city, state, zip].filter(Boolean).join(", ");
console.log(text)

.filter(Boolean) (which is the same as .filter(x => x)) removes all "falsy" values (nulls, undefineds, empty strings etc). If your definition of "empty" is different, then you'll have to provide it, for example:

 [...].filter(x => typeof x === 'string' && x.length > 0)

will only keep non-empty strings in the list.

--

(obsolete jquery answer)

var address = "foo";
var city;
var state = "bar";
var zip;

text = $.grep([address, city, state, zip], Boolean).join(", "); // foo, bar
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