ReplaceItems option doesn't works when patching/updating value with null

[J3m5]

Steps to reproduce

If you make an update with deleted properties or a patch with properties with null values, you'll get back the new items from the api without those properties.
When adding the replaceItems for the items to be completely replaced, this doesn't works because a merge is still done at the end, the items are not replaced.

Expected behavior

The replaceItems option should really replace the item.

Actual behavior

With replaceItems set to true and with an existing item, a new instance is created with the item received from the api.

feathers-vuex/src/service-module/service-module.mutations.ts

Lines 88 to 94 in 0d76efd

	if (replaceItems) {
	if (Model && !(item instanceof Model)) {
	item = new Model(item)
	}
	Vue.set(state.keyedById, id, item)
	// Merge in changes
	} else {

Then in the base model constructor, the mergeInstance mutation is called.

feathers-vuex/src/service-module/make-base-model.ts

Lines 129 to 133 in 0d76efd

	if (existingItem) {
	data = setupInstance.call(this, data, { models, store }) || data
	_commit.call(this.constructor, 'mergeInstance', data)
	return existingItem
	}

Which then call the mergeWithAccessor function

feathers-vuex/src/service-module/service-module.mutations.ts

Lines 124 to 131 in 0d76efd

	function mergeInstance(state, item) {
	const { idField } = state
	const id = getId(item, idField)
	const existingItem = state.keyedById[id]
	if (existingItem) {
	mergeWithAccessors(existingItem, item)
	}
	}

Possible solution

The mergeInstance mutation in the base model should be called only if replaceItems is not set to true.

System configuration

Module versions: 3.16.0

NodeJS version: 14.17.0

[corepay]

Hi, is this fix in a release?

[J3m5]

Hi, not yet @corepay
Any idea when you can take a look @marshallswain ?