A few months ago I worked on a legacy Typescript project where having Class files with more than 1,500 lines-of-code was quite common. A single source-file with this many lines-of-code is sometimes known as a "God Class" because it is capable of doing too many different things.

This post aims to give a walkthrough of how to design a custom ESLint rule without any prerequisites. However, some experience with Javascript Abstract Syntax Trees (ASTs) will be helpful. Consider watching my talk about getting started with ASTs. ESLint is a fantastic linting tool to help enforce your team's