In this course, we’ll start with the fundamentals of abstract syntax trees (ASTs) and learn the basic mental models. This general AST knowledge can be translated to almost any tool that works with ASTs.
Why this course?
Understanding and using ASTs unlocks the ability to make sweeping changes in a safe and reliable way in any size codebase.
Throughout this course, we’ll have converted source code into ASTs, traversed, mutated, and generated ASTs. With these concepts we’ll then explore several practical applications including things like code audits (static analysis), code transformations (codemods), and linting.
We’ll learn the fundamentals of abstract syntax trees.
- What is an AST?
- How to explore an AST
We’ll learn how to work with ASTs.
- How to turn code into an AST
- How to programmatically navigate any AST
- How to leverage TypeScript to prevent runtime errors
We’ll learn how to statically analyze, or “audit” code to understand the state of the codebase using abstract syntax trees.
- An introduction to an example codebase and refactor
- Understanding the state of the current codebase
- When to use an AST-based tool versus doing something manually
We’ll learn how to transform, or “codemod” code from one state to another using abstract syntax trees.
- How to make changes to an AST
- How to change ASTs with jscodeshift
- How to test a code transform
We’ll learn how to write rules, or “lint” code using abstract syntax trees.
- How to create rules for code
- How to create custom rules with ESLint
- How to test a rule