Ember Data - How to deserialize model.serialize()?

In Ember Data 3.24, if you do

foo = record.serialize()

how can you reverse the process? i.e. deserialize the JS object in foo and update the record?

The reverse process for Model.serialize() is Store.pushPayload():

// push some sample data into Ember Data's store
this.store.push({
  data: {
    type: 'post',
    id: '1',
    attributes: {
      title: 'foo',
    },
  },
});

// get the record    
const record = this.store.peekRecord('post', '1');

// serialize the record
const serialized = record.serialize({ includeId: true });

// manipulate the record to see the update
// this assumes that the application uses the default JSON:API serializer
serialized.data.attributes.title = 'bar';

// push the new state into the store again
this.store.pushPayload('post', serialized);

// verify that the update is reflected in Ember Data's store
console.log(record.title); // "bar"

Please note that Store.pushPayload() does not return the records which are were in the payload.

If you want to push a record into the store and get that one, you can use Store.push(). But that one expects a normalized JSON:API document following the internal conventions of Ember Data.

A payload could be normalized to a JSON:API document following the internal conventions of Ember Data with the Serializer.normalizeResponse() method. But it has a complex arguments interface, which does not fit well with the day-to-day usage of Ember Data.

// manipulate serialized state
serialized.data.attributes.title = 'baz';

// normalize the payload to JSON:API document following Ember Data's conventions
const store = this.store;
const model = this.store.modelFor('post');
const normalized = this.store.serializerFor('post').normalizeResponse(this.store, PostModel, serialized, undefined, 'findRecord');

// push it into the store
const result = this.store.push(normalized);

// verify that store has been updated
console.log(record.title); // "baz"

// Store.push() returns the record
console.log(record === result);

If only dealing with one record and not needing a fully reverse function, you may also use Store.normalize(). Assuming that your application uses JSON:API serializer the payload could also be normalized like this:

const normalized = this.store.normalize('post', serialized.data);
this.store.push(normalized);