Can I POST hasMany children as an array of POJOs on the parent?

Ember Data
2

Hi Abuelo,

There are a few separate concerns here:

  1. How does one create a record and also assign new data to its hasMany?
  2. How does one serialize a hasMany relationship as part of a payload
  3. How do you deal with a nested save

Your question so far is mostly around (1) and (2) but once you solve that you will realize you have issues with (3).

How does one create a record and also assign new data to its hasMany?

To establish relationships you can pass records into the call to createRecord. Something like this:

const order1 = store.createRecord('order', {});
const order2 = store.createRecord('order', {});
const customer = store.createRecord('customer', {
  firstName: 'Chris',
  lastName: 'Thoburn',
  orders: [ order1, order2 ]
});
await customer.save();

How does one serialize a hasMany relationship?

I’d start with reading the guide for serializers and the docs for the MinimumSerializerInterface @ember-data/serializer - 4.6 - Ember API Documentation

These will explain both when you can expect the serializer method to be called and what it should return. In your case, you’re looking to implement the serialize() method and when serializing you’ll want to include the relationships in the manner you see fit.

How do you deal with a nested save

This is a hard problem. It’s especially hard for EmberData < 3.15 beta. It get’s slightly easier from 3.15 on.

For older versions your adapter needs to keep track of the original records in the hasMany/belongsTo, and assign the appropriate ID to them from the response before returning the overall payload. This is so that the payloads in the response get correctly associated with those records as the new data is populated into the store.

This will be all that is necessary for most cases but sometimes it may result in records still being in a dirty state, if so you need to implement a transactional save model in your API, I created an example of this here: Ember Twiddle

For 3.15 beta you’d keep track of lid instead, and assign the original lid back onto the correct objects in the response either via your API or in your adapter. You shouldn’t need to do any of the transactional-save things in 3.15 beta+

You can see an example of this in EmberData’s own test suite here: data/lid-reflection-test.ts at master · emberjs/data · GitHub

Hope this helps!

Happy Trails.

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