Altercode

Altercode is a powerful TypeScript-based CLI tool/library to assist you with large-scale code transformations that can be partially automated but still require human oversight and occasional intervention. Altercode is completely open source and free to use.

Features

• Easy Configuration - Simple JSON configuration
• TypeScript Support - First-class TypeScript support
• Dry Run Mode - Test changes before applying them
• Pattern Matching - Support for both literal strings and regex patterns
• Detailed Reporting - Clear summary of all changes made
• Granular Control - Include/exclude specific files and directories

Installation

Install the package as a development dependency with the below command:

npm i sly-altercode --save-dev

Usage

1. Create a configuration file

Create a config file named altercode.config.json at the root level of your repository:

{
"sourceDir": "./src/app",
"includeExtns": [".js", ".jsx", ".ts", ".tsx"],
"excludeExtns": [".test.ts", ".enum.ts", ".constants.ts"],
"excludeDirs": ["node_modules", "dist", "build"],
"mutations": [
{ "searchString": "page-wrapper", "replaceWith": "page-container" },
{ "searchString": "const\\s+([a-zA-Z]+)\\s*=\\s*\\(\\)\\s*=>\\s*{", "replaceWith": "function $1() {",
"useRegex": true
}
]
}

2. Add the command

Add the below command in the scripts of your package.json

"scripts": {
"assist": "altercode altercode.config.json"
}

3. Run Altercode

You're all set. Now run the assist command to process your code shift tasks:

npm run assist

For a dry run (no actual file changes):

npm run assist -- --dry-run

Configuration Options

Option	Type	Description
sourceDir	string	Directory to search for files (required)
includeExtns	string[]	File extensions to include (if specified, only these will be processed)
excludeExtns	string[]	File extensions to exclude
excludeDirs	string[]	Directories to exclude from processing
mutations	Mutation[]	Array of search and replace operations

Mutation Options

Option	Type	Description
searchString	string	The string or pattern to search for (required)
replaceWith	string	The replacement string (required)
useRegex	boolean	Whether to treat searchString as a regex pattern (default: false)

Command Line Options

Option	Description
--dry-run, -d	Run without making actual changes to files

Examples

Basic String Replacement

{
"sourceDir": "./src",
"mutations": [
{ "searchString": "import React from 'react';", "replaceWith": "import * as React from 'react';" }
]
}

Using Regular Expressions

{
"sourceDir": "./src",
"mutations": [
{
"searchString": "const\\s+([a-zA-Z]+)\\s*=\\s*\\(\\)\\s*=>\\s*{",
"replaceWith": "function $1() {",
"useRegex": true
}
]
}

Working with Specific File Types

{
"sourceDir": "./src",
"includeExtns": [".tsx", ".jsx"],
"mutations": [
{ "searchString": "<div className=\"container\">", "replaceWith": "<Container>" },
{ "searchString": "</div>", "replaceWith": "</Container>" }
]
}

License

This project is licensed under the MIT license. See the LICENSE file for more info.