ES6 get nested object in array

Question

How can i find a single object which is nested deeply in an array? This is the code which works. But [0] isnt really save when it returns null or an empty array.

this.subscription = state.subscriptionsState.subscriptions
    .map(subs => subs.subscriptions.find(sub => sub.id === subscriptionId))[0];

Is there a better / nicer way?

edit: input data:

state.subscriptionsState.subscriptions = [
    {
        "name": "name",
        "type": "type",
        "subscriptions": [{
            "id": 123456,
        }]
    }
]

Answer 1

You can reduce you base Array into a 1D Array containing only the subscriptions.

From then on it's a simple .find() which returns undefined if nothing was found, or the subscription if something was found.

 'use strict' const items =[ { "name": "name", "type": "type", "subscriptions": [{ "id": 123456, }] } ] const result = items .reduce((arr, item) => arr.concat(item.subscriptions), []) .find(sub => sub.id === 123456) console.log(result) 

This should throw no errors if the base Array is empty, or if any 1st level item subscriptions Array property is empty, it would just return undefined .

Answer 2

You can use destructuring assignment to simplify this if you have ES6:

const { subscriptionsState: { subscriptions } } = state

this.subscription = subscriptions.find(s => s.id === subscriptionId)