Flop Phoenix - what is the recommended way of doing complex filters

vipulbhj

I recently started using Flop and Flop Phoenix, before this we were doing a ton of manual work. For basic filters, this makes things extremely easy, but how do you do complex filters ?

For example, assume you have

@derive {Flop.Schema,
  filterable: [
    :search,
    :status,
    :invoice_date,
    :invoice_number
  ],
  adapter_opts: [
    join_fields: [
      client_name: [
        binding: :client,
        field: :name,
        ecto_type: :string
      ]
    ],
    compound_fields: [
      search: [:invoice_number, :client_name]
    ]
  ],
  default_order: %{
    order_by: [:invoice_number],
    order_directions: [:desc]
  }
}
schema “invoices” do
  field(:invoice_number, :string)
  field(:invoice_date, :date)
  field(:status, :string)
  
  belongs_to(:client, NellieBackend.Clients.Client)

I want to setup filters with a search field that can search invoice_number and client_name, a select input with fixed values to filter on status and a date range filter for invoice_date.

Currently we are handling these manually, as I had no idea how to get this done with <.filter_fields :let={i} form={@form} fields={@fields}>

defp invoice_filters(assigns) do
  filters = assigns.meta.flop.filters || []

  search_value =
    Enum.find_value(filters, "", fn f ->
      if f.field == :search, do: f.value || ""
    end)

status_value =
  Enum.find_value(filters, "", fn f ->
    if f.field == :status && f.op == :==, do: f.value || ""
  end)

date_from_value =
  Enum.find_value(filters, "", fn f ->
    if f.field == :invoice_date && f.op == :>=, do: f.value || ""
  end)

date_to_value =
  Enum.find_value(filters, "", fn f ->
    if f.field == :invoice_date && f.op == :<=, do: f.value || ""
  end)

assigns =
  assigns
  |> assign(:search_value, search_value)
  |> assign(:status_value, status_value)
  |> assign(:date_from_value, date_from_value)
  |> assign(:date_to_value, date_to_value)

~H"""
<form phx-change="update-filter" class="border border-gray-300 rounded-xl px-6 py-4 flex flex-col gap-4 bg-white">
  <%!-- Row 1: Search and Status --%>
  <div class="flex gap-3 items-center">
    <div class="relative flex-grow">
      <.icon
        name="hero-magnifying-glass"
        class="absolute left-3 top-1/2 -translate-y-1/2 h-4 w-4 text-gray-400"
      />
      <input type="hidden" name="filters[0][field]" value="search" />
      <input type="hidden" name="filters[0][op]" value="ilike" />
      <input
        type="text"
        name="filters[0][value]"
        value={@search_value}
        placeholder="Search by invoice # or client..."
        class="w-full pl-9 pr-4 py-2 text-sm border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-transparent"
        autocomplete="off"
        phx-debounce="300"
      />
    </div>

    <div class="w-60">
      <input type="hidden" name="filters[1][field]" value="status" />
      <input type="hidden" name="filters[1][op]" value="==" />
      <select
        name="filters[1][value]"
        class="w-full px-3 py-2 text-sm border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-transparent"
      >
        <%= for {label, value} <- Invoice.status_options() do %>
          <option value={value} selected={@status_value == value}>{label}</option>
        <% end %>
      </select>
    </div>
  </div>

  <%!-- Row 2: Date Range --%>
  <div class="flex items-center gap-4">
    <div class="flex items-center gap-2">
      <label class="text-sm font-medium text-gray-700">From:</label>
      <input type="hidden" name="filters[2][field]" value="invoice_date" />
      <input type="hidden" name="filters[2][op]" value=">=" />
      <input
        type="date"
        name="filters[2][value]"
        value={@date_from_value}
        class="block rounded-md border-0 py-1.5 text-gray-900 shadow-sm ring-1 ring-inset ring-gray-300 placeholder:text-gray-400 focus:ring-2 focus:ring-inset focus:ring-indigo-600 sm:text-sm sm:leading-6"
      />
    </div>
    <div class="text-gray-400">-</div>
    <div class="flex items-center gap-2">
      <label class="text-sm font-medium text-gray-700">To:</label>
      <input type="hidden" name="filters[3][field]" value="invoice_date" />
      <input type="hidden" name="filters[3][op]" value="<=" />
      <input
        type="date"
        name="filters[3][value]"
        value={@date_to_value}
        class="block rounded-md border-0 py-1.5 text-gray-900 shadow-sm ring-1 ring-inset ring-gray-300 placeholder:text-gray-400 focus:ring-2 focus:ring-inset focus:ring-indigo-600 sm:text-sm sm:leading-6"
      />
    </div>
  </div>
</form>
"""

end

Anyone know how can we do this is a more idiomatic way ?

3 comments

/phoenix #flop_phoenix

0 551 3

2026-02-08 12:55:31 UTC

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sodapopcan

You wanna take a look at field configuration. When the fields attr is a keyword list with some specific options but you can also add any other data you need.

fields = [
  search: [
    type: text,
    label: "Invoice number / Client name",
    op: :ilike_and
  ],
  status: [
    type: :select,
    label: "Status",
    op: :==,
    options: Invoice.status_options()
  ],
  invoice_date: [
    type: :date,
    label: "Date",
    op: :==
  ],
  ...
]

~H"""
<Flop.Phoenix.filter_fields :let={i} form={@filter_form} fields={@fields}>
  <.input
    field={i.field}
    label={i.label}
    type={i.type}
    {i.rest}
    phx-debounce={i.type == "text" && "300"}
  />
</Flop.Phoenix.filter_fields>
"""

Note that i.rest is injected for you.

So this works “cleanest” when all of your inputs are the same component like in core components, but of course you can switch based of data for each field:

~H"""
<Flop.Phoenix.filter_fields :let={i} form={@filter_form} fields={@fields}>
  <.input :if={i.type == :text}  ... />
  <.select :if={i.type == :select}  ... />
</Flop.Phoenix.filter_fields>

"""

Post #1