Discover everything you need to know to get up-to-speed with JavaScript development and add dynamic enhancements to web pages. This completely updated third edition reveals how the code works and when to use closures, constants, and execution content. Starting with the basics, you'll see how to employ prototypical inheritance, as well as memory management, variable hoisting and event bubbling. Also covered is an introduction to Node.js and package managers, key to understanding the tools necessary in front-end development and how they are used with current JavaScript frameworks. JavaScript is one of the most important technologies on the web, providing the means to add dynamic functionality to your web pages and serving as the backbone of working with frameworks like Angular and React. Beginning JavaScript, Third Edition will take you from being a JavaScript novice to working freely with this important technology - begin your JavaScript journey today! What You'll Learn Construct good JavaScript syntax following modern coding practices Use JavaScript to communicate with the server and retrieve data Dynamically manipulate markup, validate forms and deal with images Debug applications using features inside the browser Use TypeScript to bring strong typing to the language Who This Book Is For Beginner to intermediate developers with a basic knowledge of front-end programming who are looking for a deeper understanding of how JavaScript works in the browser and how to answer questions in an interview.

Explore all the aspects of the Aurelia framework, including routing, templating, data binding, custom elements, event aggregation, HTTP services, features, plugins, etc. You'll see how to tie all the pieces together and walk away with an understanding of how to build applications, end to end. Practical App Development with Aurelia teaches you to write a line of business applications using simple, clean JavaScript harnessing the Aurelia framework. You'll learn the key abstractions of Aurelia and understand the life cycle of components. If you want to understand the key features of the framework and gain a mastery of building Aurelia apps, then this is the book for you. Aurelia is a modern front-end framework for mobile, desktop, and web clients. It is standards-based meaning that it has a very low learning curve. This book highlights the framework's simplicity and its power. What You'll Learn Create routes and implement pipelines Utiliize dependency injection in your classes Communicate loosely-coupled across all views Deploy your solution with minimal effort Who This Book Is For Developers, Practitioners, Programmers, and Managers who want to understand how to fundamentally create Web applications using Aurelia.

Learn to build single page web apps using Angular 5 and TypeScript by working through 70+ mini-projects. With hundreds of code examples you gain a thorough understanding of the Angular 5 ecosystem and how to work within it. You'll begin by understanding the benefits of Angular 5 vs older versions, and how this benefits your applications. You'll then move onto mini-projects that teach you JavaScript, TypeScript, how to use editors, Node, CLI, components, modules, directives, Webpack, dependency injection, widgets, routes and navigation, observers, reactive programming, and RxJS. Complete with a consistently-updated online code repository, this book is a great way to get started with Angular 5. What You'll Learn Develop single page web applications using Angular 5 Understand the web development ecosystem Use Node, JavaScript and TypeScript Who This Book Is For New or experienced developers who wish to develop single page web applications in Angular and the TypeScript language.

Developers, designers, engineers, and creators can no longer afford to pass responsibility for identity and data security onto others. Web developers who don't understand how to obscure data in transmission, for instance, can open security flaws on a site without realizing it. With this practical guide, you'll learn how and why everyone working on a system needs to ensure that users and data are protected. Authors Jonathan LeBlanc and Tim Messerschmidt provide a deep dive into the concepts, technology, and programming methodologies necessary to build a secure interface for data and identity-without compromising usability. You'll learn how to plug holes in existing systems, protect against viable attack vectors, and work in environments that sometimes are naturally insecure. Understand the state of web and application security today Design security password encryption, and combat password attack vectors Create digital fingerprints to identify users through browser, device, and paired device detection Build secure data transmission systems through OAuth and OpenID Connect Use alternate methods of identification for a second factor of authentication Harden your web applications against attack Create a secure data transmission system using SSL/TLS, and synchronous and asynchronous cryptography

R is a powerful tool for statistics and graphics, but getting started with this language can be frustrating. This short, concise book provides beginners with a selection of how-to recipes to solve simple problems with R. Each solution gives you just what you need to know to use R for basic statistics, graphics, and regression.

You'll find recipes on reading data files, creating data frames, computing basic statistics, testing means and correlations, creating a scatter plot, performing simple linear regression, and many more. These solutions were selected from O'Reilly's "R Cookbook," which contains more than 200 recipes for R that you'll find useful once you move beyond the basics.

Learn the code to write algorithms, numerical computations, data analysis and much more using the Python language: look up and re-use the recipes for your own Python coding. This book is your handy code cookbook reference. Whether you're a maker, game developer, cloud computing programmer and more, this is a must-have reference for your library. Python Recipes Handbook gives you the most common and contemporary code snippets, using pandas (Python Data Analysis Library), NumPy, and other numerical Python packages. What You'll Learn Code with the pandas (Python Data Analysis Library) Work with the various Python algorithms useful for today's big data analytics and cloud applications Use NumPy and other numerical Python packages and code for doing various kinds of analysis Discover Python's new popular modules, packages, extensions and templates library Who This Book Is For This handy reference is for those with some experience with Python.

Your full-color, friendly guide to getting started with HTML5 and CSS3! HTML and CSS are essential tools for creating dynamic websites and help make your websites even more effective and unique. This friendly-but-straightforward guide gets you started with the basics of the latest versions of HTML and CSS: HTML5 and CSS3. Introducing you to the syntax and structure of the languages, this helpful guide shows you how to create and view a web page, explains ideal usage of HTML5 and CSS3, walks you through the CSS3 rules and style sheets, addresses common mistakes and explains how to fix them, and explores interesting HTML5 tools. * Serves as an ideal introduction to HTML5 and CSS3 for beginners with little to no web development experience * Details the capabilities of HTML5 and CSS3 and how to use both to create responsive, practical, and well-designed websites * Helps you understand how HTML5 and CSS3 are the foundation upon which hundreds of millions of web pages are built * Features full-color illustrations to enhance your learning process Beginning HTML5 and CSS3 For Dummies is the perfect first step for getting started with the fundamentals of web development and design.

Learn how to use reactive architectures on the front-end. There are many technologies using a reactive approach on the back end, but this book teaches you how the reactive manifesto can be used to benefit your front-end programming as well. You will discover what reactive programming is, what the current front-end ecosystem looks like, and how to use a range of frameworks and libraries. You will also apply specific reactive architectures in your own projects. Each concept is taught with a mix of technical explanations and real-world code implementations. The future of front-end programming and architecture is reactive - don't get left behind: Add Front-End Reactive Architectures to your library today. What You'll Learn Understand when and why you should use a reactive architecture Apply a specific reactive architecture in a project Manage different reactive architectures Who This Book Is For Mid-senior front-end developers, tech leads, and solutions architects

Assess the quality of your prediction and classification models in ways that accurately reflect their real-world performance, and then improve this performance using state-of-the-art algorithms such as committee-based decision making, resampling the dataset, and boosting. This book presents many important techniques for building powerful, robust models and quantifying their expected behavior when put to work in your application. Considerable attention is given to information theory, especially as it relates to discovering and exploiting relationships between variables employed by your models. This presentation of an often confusing subject avoids advanced mathematics, focusing instead on concepts easily understood by those with modest background in mathematics. All algorithms include an intuitive explanation of operation, essential equations, references to more rigorous theory, and commented C++ source code. Many of these techniques are recent developments, still not in widespread use. Others are standard algorithms given a fresh look. In every case, the emphasis is on practical applicability, with all code written in such a way that it can easily be included in any program. What You'll Learn Compute entropy to detect problematic predictors Improve numeric predictions using constrained and unconstrained combinations, variance-weighted interpolation, and kernel-regression smoothing Carry out classification decisions using Borda counts, MinMax and MaxMin rules, union and intersection rules, logistic regression, selection by local accuracy, maximization of the fuzzy integral, and pairwise coupling Harness information-theoretic techniques to rapidly screen large numbers of candidate predictors, identifying those that are especially promising Use Monte-Carlo permutation methods to assess the role of good luck in performance results Compute confidence and tolerance intervals for predictions, as well as confidence levels for classification decisions Who This Book is For Anyone who creates prediction or classification models will find a wealth of useful algorithms in this book. Although all code examples are written in C++, the algorithms are described in sufficient detail that they can easily be programmed in any language.

Build .NET apps on Microsoft Azure services that can grow to Internet scale. Learn how you can make smart application architecture decisions and follow best practices so that your website can handle tens of thousands of concurrent users and deliver your content globally. Author Rob Reagan takes you through key Azure technologies targeted toward building web applications, and along the way shares his lessons learned in scaling out a real-world web application. After an overview of web application building blocks, the book dives into relational and NoSQL data storage options on Azure, including Azure Table Storage and CosmosDB. You'll then discover how to make best use of Redis Cache, Web Jobs, Messaging Queues, and more, alongside other tips, tricks, and troubleshooting advice for when things go wrong. The book concludes with a thorough exploration of best practices for deployment at scale. What You'll Learn Develop scalable architecture patterns on Azure with ASP.NET MVC Understand the pros and cons of using SQL Azure vs. NoSQL solutions (Azure Tables, CosmosDB) Perform data migration, backup, and recovery in SQL Azure Use effective caching Troubleshoot your web applications Know best practices for deployment Who This Book Is For Professional developers or serious hobbyists with experience developing web applications with ASP.NET MVC or Web API

Break into the most lucrative platform in the world by adding HTML5 game development to your current skillset. Zarrar Chishti has trained developers from a wide range of programming disciplines to cross over into HTML5 game development. Whatever your vocation, whether it be an Application Databases Systems developer or a Professional Web developer, with this book you will learn to evolve your current coding skills to become eligible for the biggest gaming platform in the world. From the first chapter you will see encouraging results immediately as you power through a challenging and fun project that has been uniquely designed and developed for this book. With the relentless backing of the giants of the industry including Apple and Google, HTML5 is rapidly becoming the leading technology for game development. Furthermore nearly every mobile device, tablet and PC system offer full support to the latest games developed in HTML5. Never before has there been such a widely accepted platform by literally every manufacturer and operating system. This in turn has convinced marketing departments to move away from traditional platforms, such as dedicated mobile apps, for the more widely accepted HTML5 format. There has never been a better time for a seasoned IT programmer to crossover and capitalize in this lucrative market with their much sought after talents and experience. Take the skills you already have and expand your career into HTML5 development with this book. What You'll Learn Quickly identify the core similarities and differences between HTML5 and other coding standards Follow a large scale game development project to experience the full lifecycle of an HTML5 game development project Download graphics and media to use in sample projects throughout the book Who This Book Is For Professional developers working in application and database development. These seasoned coders, having secured a wealth of knowledge, can transfer that expertise to the growing HTML5 game development market. This book will instantly appeal to this audience as it will not attempt to teach the basics of programming; instead it will simply point out the differences in how to develop with HTML5.

Discover all the new features and changes in Java 9, including module systems-JPMS or Project Jigsaw. This book covers the whole Java application development life cycle. You'll review all the important concepts, including module descriptor, unnamed module, automatic module, and command line tools. Exploring Java 9 also serves as a practical guide for migration to module systems. Code samples from real-world scenarios solidify a foundation for learning and development and allow you to apply best practices in actual development. Additionally, you'll learn about concurrency, ECMAScript 6 features in Nashorn and Parser API, stack-walking API, Stream and Optional, utilities classes, and I/O. And it's now possible to build modularized applications in Java. You'll see how JPMS affects not only the JDK itself, but also applications that are developed upon it. What You'll Learn * Build modularized applications in Java * Migrate to module systems * Master enhanced method handles Who This Book Is ForJava developers with basic development skills

Explore the features of this innovative open source language in depth, from working with the type system through object-orientation to understanding the runtime and the TypeScript compiler. This fully revised and updated second edition of Steve Fenton's popular book covers everything you need to discover this fascinating language and transform your experience of JavaScript development. What's New in This Edition Coverage of major changes to modules, namespaces, and module loading New guidance on how to use inference to reduce the effort of using TypeScript Recommendations on compiler options A wide range of feature updates from intersections and tuples to async/await and the new approach to mixins What You'll Learn Understand the TypeScript type system, and how to use it effectively Apply object-oriented design using TypeScript Use modules effectively to manage large programs Integrate existing frameworks and libraries into your TypeScript program Who This Book Is For Web developers looking for a modern approach to JavaScript development

Build fast, reliable web applications using the latest web development technologies. This book provides step-by-step learning through the process of transforming a "traditional" web app into a high-performing progressive web app, leveraging principles and lessons taught throughout the book. You will learn to improve the performance, reliability, reach, and user engagement of mobile web applications through the use of specific, practical examples. Because most non-trivial web applications developed today use JavaScript frameworks, you will learn about the most popular frameworks offering a PWA right out of the box, including React, Preact, Vue.js, Angular, and Ionic. You also will learn which tools to enlist to measure your application's performance, such as Google's Lighthouse. Beginning Progressive Web App Development includes best practices to make your app work even when an end user has a poor or no Internet connection, and to send notifications and reminders with the Notification and Push APIs to keep your users engaged. You will come away with an understanding of the technologies-application shells, server push technology, and caching-that will allow you to rapidly deliver content to your users. As important as it is to provide mobile users with a great experience, the principles of PWAs are not limited to smartphones. Most of what you will learn in this book is directly applicable to web applications on all screen sizes. What You'll Learn Achieve nearly instant loading times Implement service workers to make your app load faster and work while users are offline Keep users engaged with web notifications Measure the performance and reach of your web applications Transform your existing web app into a progressive web app Create a progressive web app from scratch Understand what building a truly fast web app entails with Google's PRPL pattern Who This Book Is For Web developers with prior JavaScript experience

Design, develop, and deploy a real-world web application by leveraging modern open source technologies. This book shows you how to use ASP.NET Core to build cross-platform web applications along with SignalR to enrich the application by enabling real-time communication between server and clients. You will use Docker to containerize your application, integrate with GitHub to package the application, and provide continuous deployment to Azure's IaaS platform. Along the way, Real-Time Web Application Development covers topics including designing a Materialize CSS theme, using a test-driven development approach with xUnit.net, and securing your application with the OAuth 2.0 protocol. To further your understanding of the technology, you will learn logging and exception handling; navigation using view components; and how to work with forms and validations. The rich code samples from this book can be used to retrofit or upgrade existing ASP.NET Core applications. What You Will Learn Design and develop a real-world web application Implement security and data storage with OAuth2 and Azure Table Storage Orchestrate real-time notifications through SignalR Use GitHub and Travis CI for continuous integration of code Master Docker containerization and continuous deployment with Docker Cloud to Azure Linux virtual machines Who This Book Is For Developers and software engineers interested in learning an end-to-end approach to application development using Microsoft technologies.

Plan how to build a better app, grow it into a business, and earn money from your hard work using Firebase. In this book, Laurence Moroney, Staff Developer Advocate at Google, takes you through each of the 15 Firebase technologies, showing you how to use them with concrete examples. You'll see how to build cross-platform apps with the three pillars of the Firebase platform: technologies to help you develop apps with a real-time database, remote configuration, cloud messaging, and more; grow your apps with user sharing, search integration, analytics, and more; and earn from your apps with in-app advertising. After reading The Definitive Guide to Firebase, you'll come away empowered to make the most of this technology that helps you build better cross-platform mobile apps using either native Android or JavaScript-based web apps and effectively deploy them in a cloud environment. What You'll Learn Use the real-time database for a codeless middleware that gives online and offline data for syncing across your users' devices Master Firebase Cloud Messaging, a technology that delivers to connected devices in less than 500ms Grow your app organically with technologies such App Indexing, App Invites, and Dynamic Links Understand problems when they arise with crash reporting Fix user problems without direct access to users' devices Tie it all together with analytics that give you great intelligence about how users interact with your app Who This Book Is For Experienced Android, mobile app developers new to Firebase. This book is also for experienced web developers looking to build and deploy web apps for smartphones and tablets, too, who may be new or less experienced with mobile programming.

This book contains tips, tricks, and techniques to make new and existing PHP applications much faster and less resource-hungry. Author Armando Padilla looks at all major sections of the PHP application stack from server hardware to database and web server performance. PHP program application performance is the center of this book, and Padilla shows you how to improve performance by best practices, proper design, and best-of-breed tools. Padilla starts out by establishing performance testing and benchmarking methodology using common open source and browser-based testing tools. He then discusses best practices for PHP development, and also explains refactoring existing code, both with performance in mind. In addition to best coding practices, this book will teach you how to use and tweak Opcode caches such as APC, XCache, and eAccelerator. Padilla then highlights how to support the efficient running of PHP applications, tweaks and settings by taking advantage of the GNU/Linux and Microsoft Windows operating systems to improve hosting performance and reliability. Additional tips on web server improvements and database administration help round out the picture.Finally, Padilla presents some hardware example configurations tuned for high performance. What you ll learn * How to improve the performance of existing PHP applications * How to maximize the performance of existing operating systems and databases * How to refactor existing PHP code for better performance * How to identify and rectify bottlenecks in PHP code * How to take advantage of variable caching to increase performance * Strategies for selecting server hardware for best performance Who this book is for This book will appeal to established PHP developers who wish to write new, complex applications or want to rearchitect existing ones. Developers of other languages such as Ruby, Python, and VB.NET will also have an interest in the techniques for tuning the performance of web servers, databases, and operating systems.

Get introduced to full stack enterprise development. Whether you are new to AngularJS and Spring RESTful web services, or you are a seasoned expert, you will be able to build a full-featured web application from scratch using AngularJS and Spring RESTful web services. Full stack web development is in demand because you can explore the best of different tools and frameworks and yet make your apps solid and reliable in design, scalability, robustness, and security. This book assists you in creating your own full stack development environment that includes the powerful and revamped AngularJS, and Spring REST. The architecture of modern applications is covered to prevent the development of isolated desktop and mobile applications. By the time you reach the end of this book you will have built a full-featured dynamic app. You will start your journey by setting up a Spring Boot development environment and creating your RESTful services to perform CRUD operations. Then you will migrate the front-end tools-AngularJS and Bootstrap-into your Spring Boot application to consume RESTful services. You will secure your REST API using Spring Security and consume your secured REST API using AngularJS. What You'll Learn Build a REST application with Spring Boot Expose CRUD operations using RESTful endpoints Create a single page application by integrating Angular JS and Bootstrap in Spring Boot Secure REST APIs using Spring Security Consume secured RESTful Services using Angular JS Build a REST client using a REST template to consume RESTful services Test RESTful services using the Spring MVC Test Framework Who This Book Is For Web application developers with previous Java programming experience who want to create enterprise-grade, scalable Java apps using powerful front tools such as AngularJS and Bootstrap along with popular back-end frameworks such as Spring Boot

Quickly learn how to get the most out of the Visual Studio for Mac integrated development environment (IDE). Microsoft has invested heavily to deliver their very best development tools and platforms to other operating systems. Visual Studio for Mac is a powerful developer tool that reinforces Microsoft's "mobile-first", "cloud-first", and "any developer, any platform, any device" strategy. With the author's guided expertise and extensive code samples, you will understand how to leverage the most useful tools in Visual Studio for Mac, the code editor, and the powerful debugger. You also will appreciate the author's guidance on collaborating with other team members using integrated tooling for the Git source control engine. Whether you are a Mac developer interested in cross-platform development or a Windows developer using a Mac, Beginning Visual Studio for Mac will quickly get you up to speed! What You'll Learn Prepare, configure, and debug in the Mac development environment Create cross-platform mobile apps for Android, iOS, and Windows with Xamarin and C# in Visual Studio for Mac Build cross-platform Web applications with .NET Core using Visual Studio for Mac Customize your productive and collaborative development environment Who This Book Is For Software developers using a Mac computer who want to build mobile or web applications that run on multiple operating systems

Embrace machine learning approaches and Python to enable automatic rendering of rich insights and solve business problems. The book uses a hands-on case study-based approach to crack real-world applications to which machine learning concepts can be applied. These smarter machines will enable your business processes to achieve efficiencies on minimal time and resources. Python Machine Learning Case Studies takes you through the steps to improve business processes and determine the pivotal points that frame strategies. You'll see machine learning techniques that you can use to support your products and services. Moreover you'll learn the pros and cons of each of the machine learning concepts to help you decide which one best suits your needs. By taking a step-by-step approach to coding in Python you'll be able to understand the rationale behind model selection and decisions within the machine learning process. The book is equipped with practical examples along with code snippets to ensure that you understand the data science approach to solving real-world problems. What You Will Learn Gain insights into machine learning concepts Work on real-world applications of machine learning Learn concepts of model selection and optimization Get a hands-on overview of Python from a machine learning point of view Who This Book Is For Data scientists, data analysts, artificial intelligence engineers, big data enthusiasts, computer scientists, computer sciences students, and capital market analysts.

Discover how to take your existing web development skills and learn how to create desktop applications for macOS, Windows, and Linux, using GitHub's Electron. Learn how to combine the power of Node.js and Chromium to provide a powerful development platform for creating web applications that break free from the browser. Electron: From Beginner to Pro guides you through the capabilities that you have available to create desktop applications. Learn to use features like file system access, create native menus, OS-specific dialogs and more. The authors will show you how to package your application for distribution for multiple platforms and enable auto-updating. What You Will Learn Leverage your knowledge of HTML, CSS and JavaScript Use current web applications for the desktop Create and use Electron's main process and render process to create effective desktop applications Communicate between processes and between windows Build desktop applications that can be updated and distributed Who This Book Is For Web developers looking to leverage their HTML, CSS and JavaScript skills to create desktop widgets and applications. Developers wanting to leverage existing a Web application to extend functionality with a desktop application.

Become a better, more productive programmer through a series of projects that will help you deeply understand and master each of the design patterns covered. In this book you will learn to write elegant "Pythonic" code to solve common programming problems. You will also experience design thinking, by identifying design patterns that would be helpful given a specific problem or situation. Python is eating the world. In recent years it has become so much more than a mere object-oriented, scripting language. Design patterns help you think of and solve problems in chunks. They help you to stand on the shoulders of the giants who have come before, instead of having to reinvent the wheel. What You Will Learn Craft cleaner code Increase your effectiveness as a programmer Write more Pythonic code Solve bigger problems Discover optimal solutions to common problems, done in a way that is uniquely Pythonic Who This Book Is For Programmers who are comfortable with Python. It is also guide for people who have mastered other programming languages and who want to make the transition to Python.

Build your next game on a bigger scale with Pro HTML5 Games. This essential book teaches you to master advanced game programming in HTML5. You'll learn techniques that you can transfer to any area of HTML5 game development to make your own professional HTML5 games. Led by an expert game programmer, you'll build two complete games in HTML5: a strategy puzzle game based on the Box2d physics engine and in the style of Angry Birds and a real-time strategy (RTS) game complete with units, buildings, path-finding, artificial intelligence, and multiplayer support. This new and fully updated second edition now includes chapters on mobile game development and an essential game developer's toolkit. Understand how to develop complex, bolder games and become an HTML5 games pro using Pro HTML5 Games today. What You'll Learn Create realistic physics in your game by incorporating the Box2d physics engine Design large worlds with lots of characters and let users interact with them Use sprite sheets, panning, parallax scrolling, and sound effects to build a more polished game Incorporate pathfinding and steering to help characters navigate through your world Create challenging levels with intelligent enemies by using decision trees, state machines, and scripted events Add multiplayer in your games using Node.js and the WebSocket API

Bring the power of functional programming to your PHP applications. From performance optimizations to concurrency, improved testability to code brevity, functional programming has a host of benefits when compared to traditional imperative programming. Part one of Pro Functional PHP Programming takes you through the basics of functional programming, outlining the key concepts and how they translate into standard PHP functions and code. Part two takes this theory and shows you the strategies for implementing it to solve real problems in your new or existing PHP applications. Functional programming is popular in languages such as Lisp, Scheme and Clojure, but PHP also contains all you need to write functional code. This book will show you how to take advantage of functional programming in your own projects, utilizing the PHP programming language that you already know. What You'll Learn Discover functional programming in PHP Work with functional programming functions Design strategies for high-performance applications Manage business logic with functions Use functional programming in object-oriented and procedural applications Employ helper libraries in your application Process big data with functional PHP Who This Book Is For Programmers and web developers with experience of PHP who are looking to get more out of their PHP coding and be able to do more with PHP.

Render high quality designs and interactive prototypes of web sites and mobile apps using Adobe XD's powerful drawing and layout tools. This book provides an in-depth look at XD and shows you how to quickly get up-to-speed to simplify these processes with intuitive design tools and a powerful prototyping function. Since the advent of the web, designers have struggled with the need to create functioning demo prototypes of their layouts and designs without an extensive amount of code for their clients. The dawn of mobile apps, which are exponentially more difficult to mock-up and demonstrate, has only intensified this problem. Beginning Adobe Experience Design resolves this for you with it's easy-to-use approach to leveraging XD. What You'll Learn Create links and interactivity to see just how your site or app will function Preview your site or prototype live in a web browser or your mobile device Use Adobe XD on both Mac and Windows Who This Book Is For Web front-end designers and user experience professionals and educators interested in teaching the tool