# Logger

A simple console log plugin to log actions as they are processed.

## Installation

```bash
npm install @ngxs/logger-plugin --save

# or if you are using yarn
yarn add @ngxs/logger-plugin
```

## Usage

Add the `NgxsLoggerPluginModule` plugin to your root app module:

```ts
import { NgxsModule } from '@ngxs/store';
import { NgxsLoggerPluginModule } from '@ngxs/logger-plugin';

@NgModule({
  imports: [NgxsModule.forRoot([]), NgxsLoggerPluginModule.forRoot()]
})
export class AppModule {}
```

### Options

The plugin supports the following options passed via the `forRoot` method:

* `logger`: Supply a different logger, useful for logging to backend. Defaults to `console`.
* `collapsed`: Collapse the log by default or not. Defaults to `true`.
* `disabled`: Disable the logger during production. Defaults to `false`.
* `filter`: Filter actions to be logged. Takes action and state snapshot as parameters. Default predicate returns `true` for all actions.

```ts
import { NgxsModule, getActionTypeFromInstance } from '@ngxs/store';
import { NgxsLoggerPluginModule } from '@ngxs/logger-plugin';
import { environment } from '../environments/environment';
import { customLogger } from './path/to/custom/logger';
import { SomeAction } from './path/to/some/action';

@NgModule({
  imports: [
    NgxsModule.forRoot([]),
    NgxsLoggerPluginModule.forRoot({
      // Use customLogger instead of console
      logger: customLogger,
      // Do not collapse log groups
      collapsed: false,
      // Do not log in production mode
      disabled: environment.production,
      // Do not log SomeAction
      filter: action => getActionTypeFromInstance(action) !== SomeAction.type
    })
  ]
})
export class AppModule {}
```

> The `filter` predicate takes state snapshot as the second parameter. This should prove useful for some edge cases. However, beware of the fact that the predicate is called for every action dispatched. You may consider using a memoized function for filters more complicated than a simple action comparison.

### Notes

You should always include the logger as the last plugin in your configuration. For instance, if you were to include logger before a plugin like the storage plugin, the initial state would not be reflected.