Simplify simple ternary expression

Question

I want to validate undefined attributes from an object so I use ternary like this

item.subitem ? item.subitem.toString() : ''

Is there any way to simplify this expression using || or && ?

I usually have `const string = value => value == null? "": String(value);` defined somewhere in my code, among a few others. Then it's just `string(item.subitem);` — Thomas, Feb 25 '19 at 06:01

Bhojendra Rauniyar · Accepted Answer · 2019-02-28T02:35:50.757

3

It's simple:

item.subitem && item.subitem.toString() || ''

Or simply like:

(item.subitem || '').toString()

OR,

''+(item.subitem || '')

If you can use optional chaining, then it can be even more simple:

item.subitem?.toString()

See this post for more detail.

As @Thomas mentioned in comment, you can also use an array and convert to a string:

[item.subitem].toString();

This should clear how it will work:

[].toString(); // ''
[undefined].toString(); // ''
['foo'].toString(); // 'foo'
['foo', 'bar'].toString(); 'foo,bar'

edited Feb 28 '19 at 02:35

answered Feb 25 '19 at 05:51

The first example uses more bytes than the code at the question. – guest271314 Feb 25 '19 at 06:03
2

Yeah, but I have just provided it for OP curiosity. – Bhojendra Rauniyar Feb 25 '19 at 06:07
when we're already at hacks do you know this one: `""+[item.subitem]` – Thomas Feb 27 '19 at 20:47

score 1 · Answer 2 · answered Feb 25 '19 at 05:53

1

Yes you can

(item.subitem || '').toString()

answered Feb 25 '19 at 05:53

Code Maniac

2 Answers2