Maintaining and refactoring a large codebase requires lots of development time and effort. Issues, such as inconsistencies in variable naming or passing incorrect arguments in function calls, tend to happen more frequently in larger codebases. As you scan your codebase for these issues, you may observe some of them emerging repeatedly in different parts of your codebase. Manually sifting through tens and hundreds of files to apply the same set of changes in multiple places is simply not feasible. Anytime you have to manually make many repetitive changes, the likelihood of a mistake occurring increases. To automate this entire process, you need tooling that draws upon abstract syntax trees to audit code, report the findings and, if warranted, immediately resolve them. Abstract syntax trees are not only used for compilers; they are also present in other types of development tooling. By parsing source code into an abstract syntax tree, we can traverse the nodes of the tree to interact directly with each and every literal, identifier, etc. in the source code. For React applications, auditing with abstract syntax trees lets us understand the current state of our components' source code and get information about our components' contents. For example, if we notice elements scattered throughout our application, then we can write a tool to list the CSS classes assigned to their className attributes. Using this list, we can check if there are any incorrectly spelled CSS classes and/or invalid CSS classes and fix them. Additionally, we can refactor the elements into a component and consolidate the CSS classes within this single component. Therefore, if we decide to rename/remove any of the CSS classes, then we only need to visit and edit one component instead of many.

You may have seen the term "abstract syntax trees", "AST", or maybe even learned about them in a computer science curriculum, but chalked them up as being irrelevant to the work you need to do as a frontend engineer. On the contrary, abstract syntax trees are ubiquitous in the frontend ecosystem. Understanding abstract syntax trees isn't a requirement for being a productive or successful frontend engineer, but it can unlock a new skill set that has many practical applications in frontend development. First, what are abstract syntax trees? In the simplest form, an abstract syntax tree is a way to represent code so a computer can understand it. The code we write is a giant string of characters that will only do something if a computer can understand and interpret the code.

Learn the practical techniques you need today to modify any large-scale codebase without the hassle of manual, one line at a time refactors.  We use real world tools such as Facebook's jscodeshift to apply these powerful concepts on actual codebases. The course goes beyond just theory to practical hands on coding , with a sample codebase we provide that you will modify as you apply the techniques you learn in the course. With  Practical Abstract Syntax Trees  you  unlock the ability to make sweeping changes in a safe and reliable way in any size codebase . We'll tackle: