How can I implement a form with m2m field (select shown in the screenshot)?

I would like to emphasize that this is not a dynamic form, an example of which can be found in the repository GitHub - LostKobrakai/one-to-many-form: Example repo for blogpost · GitHub, but it’s a field.

I also know about the possibility of linking via put_assoc in the documentation, which fits this case (Adding tag to a post Ecto.Changeset — Ecto v3.14.0), but it doesn’t mention anything about form implementation.

I also know about live_select, phx-multi-select, etc, It isn’t about component implementation

It’s about matchig schema to form

  schema "projects" do
    field :name, :string
    field :description, :string
    has_many :locales, Locales, on_replace: :delete
    belongs_to :team, Team
    belongs_to :base_language, Language

    many_to_many :languages, Language,
      join_through: Locale,
      on_replace: :delete

    timestamps type: :utc_datetime
  end

and make multi selection for locales field. I don’t understand, what do I have to work with? Language labels, id languages?

Implemented this via virtual fields, but it seems like I’m doing it wrong

1. There is a Project that is linked to Languages through an intermediate table runa/lib/domains/projects/project.ex at 6cced23a560c0780391c8268563d587bda347290 · ravecat/runa · GitHub
2. Passing virtual field to form fields runa/lib/application/live/project/form.ex at 6cced23a560c0780391c8268563d587bda347290 · ravecat/runa · GitHub and processed during validation in the same component.
3. in the changset for the form I already bind by real fields runa/lib/domains/projects/project.ex at 6cced23a560c0780391c8268563d587bda347290 · ravecat/runa · GitHub

it seems that this approach complicates and contains the issues and could be done more simply (edited)

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