How to default to empty array if property does not exist - es6

Question

I have the following code to get barNames from an object bar:

const {[id]: {'name': fooName} = []} = foo || {};
const {'keywords': {[fooName]: barNames}} = bar || [];

Note: fooName exists, but doesn't exist in keywords as a property

I want to make barNames an empty array if an object fooName does not exist in bar.keywords. I tried to to use the OR operator but it doesn't seem to work. I don't want to use any more ternary operators like ?, :, &&, etc.

Any hints would be nice.

This ended up working better: const barNames = bar.keywords[fooName] || [] — amigo21
– amigo21, Commented Jun 13, 2018 at 16:08
It's not just working better, it's the only way it's working. bar || ... could be used only if bar were undefined. Btw, it's logical OR, not a pipe. — Estus Flask
– Estus Flask, Commented Jun 13, 2018 at 16:11

Bergi · Accepted Answer · 2018-06-13 17:43:34Z

1

I think you're looking for a default initialiser:

const {[id]: {'name': fooName}} = foo || {};
const {'keywords': {[fooName]: barNames = []}} = bar || {};
//                                      ^^^^

answered Jun 13, 2018 at 17:43

Bergi

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1 Comment

amigo21 Over a year ago

Yes! Initializing the barNames array to empty is the solution. thanks

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