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TypeScript Developer Tools

Table of contents

Description

A collection of AST (Abstract Syntax Tree) transformation scripts to automate tedious tasks in TypeScript codebases.

As your codebase grows, it becomes difficult to make a refactoring, enforce a certain coding style, or add some new functionality in many places. This repository contains scripts that help you to automate these tasks using scripts that traverse the AST of your TypeScript codebase, detect certain patterns, and modify the codebase accordingly. These scripts are written in TypeScript and use ts-morph library to traverse and modify the codebase.

You can paste (the part) of your code into the TypeScript AST Viewer to see the AST of your code. This will help you to understand how the scripts work.

Usage

First, you need to install dev dependencies:

npm install typescript ts-node ts-morph --save-dev

Then copy the script you want to use to your project. I suggest you to put scripts to the separate directory (e.g. ./scripts/) and add exclude it from compilation in tsconfig.json:

{
  "compilerOptions": {
    // ...
  },
  "exclude": ["node_modules", "dist", "scripts"]
}

Then you can add commands to your package.json. You may look at the package.json file in this repository for inspiration.

Common patterns in scripts usage

Here are some common patterns used in any script:

  1. To run the script, run ts-node ./<your-scripts-directory>/<script-name> --glob='<your-glob>'.
  2. Every script needs a glob parameter, which is a path to the files you want to be traversed by the script. E.g. if you want the script to traverse all .ts and .tsx files in src/ directory and its subdirectories, you can use --glob='src/**/*.(ts|tsx)'. If you don't provide the glob parameter, the script will print the help message to the stderr and exits with code 1.
  3. Running any script with glob parameter only is not destructive! The script will not modify your codebase. It only prints the table with the changes it will make if you pass the --fix parameter. E.g. if you run a no-console script with the glob parameter only, it will print the table with files and line numbers where the console calls are found.
  4. If you want to apply the changes, you need to run the script with --fix parameter. E.g. ts-node ./<your-scripts-directory>/<script-name> --glob='src/**/*.(ts|tsx)' --fix. It will print the table with files and line numbers where the console calls were removed.

NOTE: Exclude in your glob parameter the node_modules and the dist directories. Or pass only those directories where your code is located. E.g. prisma generates a lot of the boilerplate code and you definitely don't want to touch it with the script.

Scripts

no-console

Details

Parses the code to the Abstract Syntax Tree and traverses all its nodes to find console.* calls.

If you don't pass the --fix parameter, it will only print the table with files and line numbers where the console calls are found.

Pass the --fix parameter to remove all console calls from the codebase. The script will notify you about the changes it made.

no-unused-exports

Details

Although you can add to the compilerOptions in tsconfig.json the noUnusedLocals option, developers often bypass it by exporting unused variables, classes, enums, interfaces, etc. As your codebase grows, the number of unused exports will grow too.

This script finds all the exports with no references in other files and removes the export keyword from such the exported declarations (if you pass the --fix parameter to the script). If the --fix parameter is not passed, the script will only print the table with files, line numbers, and unused declaration types and names, where the unused exports are found.

NOTE: Let the script traverse all your codebase. If you exclude some directories, the script will not be able to check for an external reference of the exported declaration in excluded files. This can result in false positives.

NOTE: The script will not remove the unused exported declarations. It only removes the export keyword from the declaration and leaves the declaration in the codebase even if it has no references at all. Set the noUnusedLocals option in the compilerOptions in tsconfig.json to true to let the TypeScript compiler notify you about unused declarations after the script had removed the export keyword from them.