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# EctoNestedChangeset
This is a package for manipulating nested
[Ecto](https://github.com/elixir-ecto/ecto) changesets.
## Installation
Add `ecto_nested_changeset` to your list of dependencies in `mix.exs`:
```elixir
def deps do
[
{:ecto_nested_changeset, "~> 1.0.0"}
]
end
```
## Usage
The primary use case of this library is the manipulation of
[Ecto](https://github.com/elixir-ecto/ecto) changesets
used as a source for dynamic, nested forms in
[Phoenix LiveView](https://github.com/phoenixframework/phoenix_live_view).
```elixir
category = %Category{
posts: [
%Post{
id: 1,
comments: [
%Comment{body: "potato", id: 1},
%Comment{body: "you", id: 2}
],
title: "must"
},
%Post{comments: [], id: 2, title: "young"}
]
}
category
|> Ecto.Changeset.change()
|> append_at(:posts, %Post{title: "Padawan", comments: []})
|> prepend_at([:posts, 0, :comments], %Comment{body: "ecneitaP"})
|> delete_at([:posts, 0, :comments, 1], mode: {:action, :delete})
|> insert_at([:posts, 1], %Post{title: "have"})
|> append_at([:posts, 2, :comments], %Comment{body: "my"})
|> update_at([:posts, 0, :comments, 0, :body], &String.reverse/1)
|> Ecto.Changeset.apply_changes()
%Category{
posts: [
%Post{
comments: [
%Comment{body: "Patience"},
%Comment{body: "you", id: 2}
],
id: 1,
title: "must"
},
%Post{title: "have"},
%Post{
comments: [%Comment{body: "my"}],
id: 2,
title: "young"
},
%Post{title: "Padawan"}
]
}
```
## Example application
There is an example Phoenix application with a dynamic nested LiveView form in
the `/example` folder of the repository.
```bash
git clone https://github.com/woylie/ecto_nested_changeset.git
cd ecto_nested_changeset/example
mix setup
mix phx.server
```
Note that Postgres needs to be running to use the application.
You can access the application at http://localhost:4000.
## Status
This library is actively maintained, but given its narrow purpose, it will not
see frequent updates.
