---
title: SolidartObserver API docs
description: All the API docs of SolidartObserver
---
> ## Documentation Index
> Fetch the complete documentation index at: https://docs.page/nank1ro/solidart/llms.txt
> Use this file to discover all available pages before exploring further.

# SolidartObserver API docs

An object that listens to the changes of the reactive system.

This can be used for logging purposes.

## `void didCreateSignal(SignalBase<Object?> signal)`

Called when a new signal is created.

## `void didUpdateSignal(SignalBase<Object?> signal)`

Called when a signal is updated.

## `void didDisposeSignal(SignalBase<Object?> signal)`

Called when a signal is disposed.

---

```dart
import 'dart:developer' as dev;

class Logger implements SolidartObserver {
  @override
  void didCreateSignal(SignalBase<Object?> signal) {
    dev.log(
        'didCreateSignal(name: ${signal.options.name}, value: ${signal.value})');
  }

  @override
  void didDisposeSignal(SignalBase<Object?> signal) {
    dev.log('didDisposeSignal(name: ${signal.options.name})');
  }

  @override
  void didUpdateSignal(SignalBase<Object?> signal) {
    dev.log(
        'didUpdateSignal(name: ${signal.options.name}, previousValue: ${signal.previousValue}, value: ${signal.value})');
  }
}
```