codemad

Mod that code like you're mad!

This package allows you to write simple code mods. It allows you to transform JSON, Typescript and plain text files.

Installation

npm i -D codemad

Usage

This library is meant to be used as a library inside a node utility. The fluent style API and can be chained. The file matching is provided by the glob utility. See the glob documentation for details on what can be passed into the matcher syntax.

The API

// The JSON object is passed into the callback, it expects a serializable object to be written to disk
mod('some file pattern').asJson(json => {
  //...
});

// The text is given to a callback, return a transformed text to overwrite the original file
mod('some file pattern').asText(text => {
  //...
});

// This mod uses the transformer API from Typescript. Provide a visitor function as a callback
mod('some file pattern').asTypescript(node => {
  //...
});

To modify text

import mod from 'codemad';

mod('config.txt').asText(text => {
  return text.replace('hello', 'world');
});

To modify JSON

import mod from 'codemad';

interface PackageJson {
  version: string;
}

mod('package.json').asJson((json: PackageJson) => {
  // JSON can be typed
  json.version = '1.0.0'; // Change the JSON
  return json; // Important: be sure to return a serializable JSON
}, 2); // The API also can take in an optional number of spaces for indentation

To modify Typescript

import mod from 'codemad';

mod('src/test.ts').asTypescript((node, modder) => {
  if (ts.isExpressionStatement(node)) {
    for (let child of node.getChildren()) {
      if (ts.isCallExpression(child)) {
        return modder.prepend(node, 'console.log("hi");');
      }
    }
  }
});

There are several APIs that you can use with the modder object:

• prepend(node: ts.Node, content: string)
• append(node: ts.Node, content: string)
• replace(node: ts.Node, content: string)
• remove(node: ts.Node, content: string)
• removeFull(node: ts.Node, content: string)

The difference between remove() and removeFull() is that the removeFull() version will remove whitespace before and after the node. This is a clean way to remove full statements, for example without leaving whitespace or blank lines in the area of the removed node.