Uuuh nice! That’s even cleaner than to manipulate the query params. Thanks!
kevinschweikert
LostKobrakai
Yes. Imo directly manipulating params is a sign of bad abstraction. It means your code doesn’t want to deal with the fact that indeed not all changes are provided by params.
1
kevinschweikert
For anybody finding this thread and needing a solution for the preselection:
def mount(_params, _session, socket) do
categories = [%Category{id: 0, name: "Category 1", preselected: true}, %Category{id: 1, name: "Category 2", preselected: false}]
preselected = Enum.filter(categories, & &1.preselected) |> Enum.map(& &1.id)
categories_form = parse_filter(%{all: false, selected: []}, %{all: false, selected: preselected})
categories_filter = apply_filter(categories_form)
categories_options = Enum.map(categories, &{&1.name, &1.id})
{:ok,
assign(socket,
categories: categories,
filtered_categories: filter_categories(categories, categories_filter),
filter: categories_filter,
options: categories_options,
preselected: preselected
)
|> assign_form(categories_form)}
end
def handle_params(params, _, socket) do
form =
parse_filter(socket.assigns.filter, params)
|> maybe_add_preselected(socket.assigns.preselected)
filter = apply_filter(form)
{:noreply,
socket
|> assign(
filter: filter,
filtered_categories: filter_categories(socket.assigns.categories, filter),
preselected: []
)
|> assign_form(form)}
end
@spec maybe_add_preselected(Ecto.Changeset.t(), [integer()]) :: Ecto.Changeset.t()
defp maybe_add_preselected(changeset, preselected) when preselected == [], do: changeset
defp maybe_add_preselected(changeset, preselected) do
case Ecto.Changeset.fetch_change(changeset, :selected) do
{:ok, []} -> Ecto.Changeset.change(changeset, selected: preselected)
_ -> changeset
end
end
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