Introduction to logkitty

logkitty is a powerful library for React Native and Android development that allows developers to easily access and filter logcat logs. It provides a rich set of APIs to help you streamline the debugging process and enhance your development workflow. In this article, we will explore dozens of useful APIs provided by logkitty with code snippets, and we will also build a simple app to demonstrate these features in action.

Getting Started with logkitty

First, you need to install logkitty.

  
    npm install logkitty
  

Useful APIs of logkitty

1. Basic Usage

Fetch all logcat logs.

  
    const { spawn } = require('logkitty');

    const reader = spawn('adb logcat');
    reader.on('entry', entry => {
      console.log(entry);
    });
  

2. Filtering Log Levels

Filter logs by level: verbose, debug, info, warn, error, fatal.

  
    const { spawn, Level } = require('logkitty');

    const reader = spawn('adb logcat', {
      filter: [{ tag: '*', level: Level.DEBUG }],
    });

    reader.on('entry', entry => {
      console.log(entry);
    });
  

3. Filtering Tags

Filter logs by specific tags.

  
    const { spawn } = require('logkitty');

    const reader = spawn('adb logcat', {
      filter: [{ tag: 'ReactNativeJS' }],
    });

    reader.on('entry', entry => {
      console.log(entry);
    });
  

4. Setting Log Patterns

Set patterns to display specific log messages.

  
    const { spawn, match, formatEntry, formatMessage } = require('logkitty');

    const reader = spawn('adb logcat', {
      filter: [match('ReactNativeJS')],
      uncolored: true,  // If you want raw logs instead of colored ones
    });

    reader.on('entry', entry => {
      console.log(formatEntry(entry));
    });
  

5. Using Custom Handlers

Handle log entries with custom functions.

  
    const { spawn } = require('logkitty');

    const reader = spawn('adb logcat');

    reader.on('entry', entry => {
      if (entry.message.includes("ERROR")) {
        console.error("Custom Error Handler: ", entry);
      } else {
        console.log(entry);
      }
    });
  

Building a Simple App with logkitty Integration

Let’s create a simple React Native app that integrates logkitty for logging and debugging.

  
    // App.js
    import React, { useEffect } from 'react';
    import { View, Text } from 'react-native';
    const { spawn, match, formatEntry } = require('logkitty');

    const App = () => {
      useEffect(() => {
        const reader = spawn('adb logcat', {
          filter: [{ tag: 'ReactNativeJS', level: 'DEBUG' }],
          uncolored: true,
        });

        reader.on('entry', entry => {
          console.log(formatEntry(entry));
        });

        return () => {
          reader.removeAllListeners('entry');
        }
      }, []);

      return (
        
          Hello World
        
      );
    };

    export default App;
  

In this app, we use useEffect to start the logkitty reader when the component mounts, and clean up the listener when the component unmounts. This captures and logs messages tagged with ‘ReactNativeJS’ at the ‘DEBUG’ level, providing real-time logging information for our app.

Conclusion

logkitty is a versatile tool that simplifies the process of accessing and filtering logcat logs, making debugging in React Native more efficient. Whether you need basic log fetching, filtering by levels or tags, or custom log handling, logkitty offers a comprehensive solution to meet your needs.

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