Part of T171725: Add snak hashes to entity HTML output is to make sure the hashes are also present in snak DOM elements constructed client-side, e. g. after editing. This means that the snak needs to be persisted in the JS datamodel, so that the statement deserializer (or rather, the deserializers it uses) can store the hash from the API response in the datamodel object, where the view can then take it and apply it to the DOM.
Pull requests: