# LifeCycleHook

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<!-- MDOC !-->

LifeCycleHook is a simple hook that logs each life-cycle step of LiveView.

It is good for learning Phoenix LiveView life-cycle.

## Overview

By mounting `LifeCycleHook` on LiveView with `use LifeCycleHook`, you can see logs for each life-cycle of LiveView.

```elixir
defmodule MyApp.MyLive do
  use Phoenix.LiveView
  use LifeCycleHook

  @impl true
  def render(assigns) do
    ...
  end

  @impl true
  def handle_event("click", params, socket) do
    ...
  end
end
```

```
[debug] Elixir.MyApp.MyLive mount with HTTP
[debug] Elixir.MyApp.MyLive handle_params with HTTP
[debug] Elixir.MyApp.MyLive mount with WebSocket
[debug] Elixir.MyApp.MyLive handle_params with WebSocket

[debug] Elixir.MyApp.MyLive handle_event event: click
```

### only/except options

If you want to choose specific stages to log, you can use `only` or `except` option in `use LifeCycleHook`.
For example, you can set `only: [:mount]` option to use `LifeCycleHook` in sticky nested LiveView which doesn't support `handle_params` hook.

```elixir
defmodule MyApp.MyStickyNestedLive do
  use Phoenix.LiveView
  use LifeCycleHook, only: [:mount]

  @impl true
  def render(assigns) do
    ...
  end
end
```

```
[debug] Elixir.MyApp.MyStickyNestedLive mount with HTTP
[debug] Elixir.MyApp.MyStickyNestedLive mount with WebSocket
```

### log_level option

You can change log level of `LifeCycleHook` with `log_level` option.

```elixir
defmodule MyApp.MyWarnLogLevelLive do
  use Phoenix.LiveView
  use LifeCycleHook, log_level: :warn

  @impl true
  def render(assigns) do
    ...
  end
end
```

```
[warning] Elixir.MyApp.MyWarnLogLevelLive mount with HTTP
[warning] Elixir.MyApp.MyWarnLogLevelLive mount with WebSocket
```

## Installation

The package can be installed by adding `:life_cycle_hook` to your list of
dependencies in `mix.exs`:

```elixir
def deps do
  [
    {:life_cycle_hook, "~> 0.6"}
  ]
end
```
<!-- MDOC !-->

## TO DO

- [x] Add `handle_params` hook
- [x] Add macro that replace `on_mount({LifeCycleHook, __MODULE__})`
- [ ] Support nested LiveView with `sticky: true` option
- [x] Add `handle_event` hook
- [ ] Add `handle_info` hook
- [x] Support `only`, `except` options in `use LifeCycleHook`
- [x] Support setting log level
- [ ] Support watching params of each hook
- [ ] Support LiveComponent
- [ ] Remove `Elixir` prefix from module names in logs

## Copyright and License

Copyright (c) 2022 Jinkyou Son (Json)

This work is free. You can redistribute it and/or modify it under the
terms of the MIT License. See the [LICENSE.md](./LICENSE.md) file for more details.