Fowler M. Refactoring. Improving the Design of...Code 2ed 2019

Textbook in PDF format

For more than twenty years, experienced programmers worldwide have relied on Martin Fowler’s Refactoring to improve the design of existing code and to enhance software maintainability, as well as to make existing code easier to understand.
This eagerly awaited new edition has been fully updated to reflect crucial changes in the programming landscape. Refactoring, Second Edition, features an updated catalog of refactorings and includes JavaScript code examples, as well as new functional examples that demonstrate refactoring without classes.
Like the original, this edition explains what refactoring is; why you should refactor; how to recognize code that needs refactoring; and how to actually do it successfully, no matter what language you use.
* Understand the process and general principles of refactoring
* Quickly apply useful refactorings to make a program easier to comprehend and change
* Recognize “bad smells” in code that signal opportunities to refactor
* Explore the refactorings, each with explanations, motivation, mechanics, and simple examples
* Build solid tests for your refactorings
* Recognize tradeoffs and obstacles to refactoring