mrm-core

Utilities to write codemods for config files (JSON, YAML, INI, Markdown, etc.). Can be used to make tasks for Mrm.

Example

Add ESLint to your project:

const { json, lines, packageJson, install } = require('mrm-core');

module.exports = function(config) {
  const preset = config('preset', 'tamia');
  const packages = ['eslint', `eslint-config-${preset}`];

  // .eslintrc
  const eslintrc = json('.eslintrc');
  if (!eslintrc.get('extends').startsWith(preset)) {
    eslintrc.set('extends', preset).save();
  }

  // .eslintignore
  lines('.eslintignore')
    .add('node_modules')
    .save();

  // package.json
  const pkg = packageJson()
    .setScript('lint', 'eslint . --fix')
    .setScript('pretest', 'npm run line')
    .save();

  // Install dependencies
  install(packages);
};
module.exports.description = 'Adds ESLint with a custom preset';

Read more in the docs, and this task is already included by default.

You can find more examples in my dotfiles repository.

You don’t have to use mrm-core with mrm, you can run this tasks from your own code:

const get = require('lodash/get');
const addEslint = require('./tasks/eslint');
const config = {
  preset: 'airbnb'
};
const getConfig = (prop, defaultValue) =>
  get(config, prop, defaultValue);
addEslint(getConfig);

Installation

npm install mrm-core

API

Work with files

Do not overwrite original files, unless you want to.
All functions (except getters) can be chained.
save() will create file if it doesn’t exist or update it with new data.
save() will write file to disk only if the new content is different from the original file.
save() will try to keep formatting (indentation, end of file new line) of the original file or use style from EditorConfig.

JSON

API:

const { json } = require('mrm-core');
const file = json('file name', { default: 'values' });
file.exists(); // File exists?
file.get(); // Return everything
file.get('key.subkey', 'default value'); // Return value with given address
file.set('key.subkey', 'value'); // Set value by given address
file.set({ key: value }); // Replace JSON with given object
file.unset('key.subkey'); // Remove value by given address
file.merge({ key: value }); // Merge JSON with given object
file.save(); // Save file
file.delete(); // Delete file

Example:

json('.eslintrc')
  .merge({
    extends: 'eslint-config-recommended'
  })
  .save();

YAML

API:

const { yaml } = require('mrm-core');
const file = yaml(
  'file name', // File name
  { default: 'values' }, // Default value
  { version: '1.2' } // Options
);
file.exists(); // File exists?
file.get(); // Return everything
file.get('key.subkey', 'default value'); // Return value with given address
file.set('key.subkey', 'value'); // Set value by given address
file.set({ key: value }); // Replace JSON with given object
file.unset('key.subkey'); // Remove value by given address
file.merge({ key: value }); // Merge JSON with given object
file.save(); // Save file
file.delete(); // Delete file

Example:

yaml('.travis.yml')
  .set('language', 'node_js')
  .set('node_js', [4, 6])
  .save();

INI

API:

const { ini } = require('mrm-core');
const file = ini('file name', 'comment');
file.exists(); // File exists?
file.get(); // Return everything
file.get('section name'); // Return section value
file.set('section name', { key: value }); // Set section value
file.unset('section name'); // Remove section
file.save(); // Save file
file.save({ withSpaces: false }); // Disable spaces around =
file.delete(); // Delete file

Example:

const { ini } = require('mrm-core');
ini('.editorconfig', 'editorconfig.org')
  .set('_global', { root: true })
  .set('*', {
    indent_style: 'tab',
    end_of_line: 'lf'
  })
  .save();

Result:

# editorconfig.org
root = true

[*]
indent_style = tab
end_of_line = lf

New line separated text files

API:

const { lines } = require('mrm-core');
const file = lines('file name', ['default', 'values']);
file.exists(); // File exists?
file.get(); // Return everything
file.set(['line 1', 'line 2', 'line 3']); // Set file lines, overwrite existing
file.add('new'); // Add new line
file.add(['new', 'lines']); // Add multiple news lines
file.remove('new'); // Remove line
file.remove(['new', 'lines']); // Remove multiple lines
file.save(); // Save file
file.delete(); // Delete file

Example:

lines('.eslintignore')
  .add('node_modules')
  .save();

Markdown

Note: use template function to create Markdown files.

API:

const { markdown } = require('mrm-core');
const file = markdown('file name');
file.exists(); // File exists?
file.get(); // Return file content
// Add a badge at the beginning of the file (below header)
file.addBadge('image URL', 'link URL', 'alt text');
// Remove a badge when the predicate function returns true
file.removeBadge(({ imageUrl, linkUrl, altText }) =>
  imageUrl.startsWith('https://travis-ci.org')
);
file.save(); // Save file
file.delete(); // Delete file

Example:

const name = 'pizza';
markdown('Readme.md')
  .addBadge(
    `https://travis-ci.org/${config('github')}/${name}.svg`,
    `https://travis-ci.org/${config('github')}/${name}`,
    'Build Status'
  )
  .save();

Plain text templates

Templates use ECMAScript template literals syntax.

API:

const { template } = require('mrm-core');
const file = template('file name', 'template file name');
file.exists(); // File exists?
file.get(); // Return file content
file.apply({ key: 'value' }); // Replace template tags with given values
file.save(); // Save file
file.delete(); // Delete file

Example:

template('License.md', path.join(__dirname, 'License.md'))
  .apply(config(), {
    year: new Date().getFullYear()
  })
  .save();

Template:

The MIT License
===============

Copyright ${year} ${name} (${url}), contributors

Permission is hereby granted, free of charge, to any person obtaining...

Special files

package.json

API:

const { packageJson } = require('mrm-core');
const file = packageJson({ default: 'values' });
file.exists(); // File exists?
file.get(); // Return everything
file.getScript('test'); // Return script
file.getScript('test', 'eslint'); // Return a subcommand of a script
file.setScript('test', 'eslint --fix'); // Replace a script with a command: a -> b
file.appendScript('test', 'eslint --fix'); // Append command to a script: a -> a && b
file.prependScript('test', 'eslint --fix'); // Prepend a script with a command: a -> b && a
file.removeScript('test'); // Remove script
file.removeScript(/^mocha|ava$/); // Remove all scripts that match a regexp
file.removeScript('test', /b/); // Remove subcommands from a script: a && b -> a
file.save(); // Save file
file.delete(); // Delete file
// All methods of json() work too

Note: subcommand is a command between && in an npm script. For example, prettier --write '**/*.js' && eslint . --fix has two subcommands: prettier… and eslint….

Example:

packageJson()
  .appendScript('lint', 'eslint . --ext .js --fix')
  .save();

File system helpers

const { copyFiles, deleteFiles, makeDirs } = require('mrm-core');
copyFiles('source dir', 'file name'); // Copy file
copyFiles('source dir', ['file name 1', 'file name 2']); // Copy files
copyFiles('source dir', 'file name', { overwrite: false }); // Do not overwrite
deleteFiles('file name 1'); // Delete file or folder
deleteFiles(['file name 1', 'folder name 1']); // Delete files or folders
makeDirs('dir name'); // Create folder
makeDirs(['dir name 1', 'dir name 2']); // Create folders

Install and uninstall npm, Yarn, or pnpm packages

Installs npm package(s) and saves them to package.json if they aren’t installed yet or not satisfying range.

const { install } = require('mrm-core');
install('eslint'); // Install to devDependencies
install(['tamia', 'lodash'], { dev: false }); // Install to dependencies
install({ lodash: '^4.17.3' }); // Install particular version
install(['lodash'], {
  versions: { lodash: '^4.17.3', other: '1.0.0' }
}); // Install particular version
install(['github/repo']); // Install non-registry package without version

Note: Works with all semver ranges, like 1.2.3, ^1.2.0 or >=2.

Uninstalls npm package(s) and removes them from package.json:

const { uninstall } = require('mrm-core');
uninstall('eslint'); // Uninstall from devDependencies
uninstall(['tamia', 'lodash'], { dev: false }); // Uninstall from dependencies

To use Yarn pass yarn: true:

const { install, uninstall } = require('mrm-core');

uninstall(['eslint'], { yarn: true });
install(['standard'], { yarn: true });

With Yarn Berry, pass yarnBerry: true and for pnpm, pass pnpm: true.

Utilities

Infers style (indentation, new line at the end of file) from a source code or reads from the .editorconfig file.

const {
  inferStyle,
  getStyleForFile,
  getIndent,
  format
} = require('mrm-core');
inferStyle('for (;;) {\n  alert(1);\n}\n');
// => { insert_final_newline: true, indent_style: 'space', indent_size: 2 }
getStyleForFile('test.js');
// => { insert_final_newline: false, indent_style: 'tab', indent_size: 'tab' }
getIndent({ indent_style: 'space', indent_size: 2 });
// => '  '
format('alert(1)\n', { insert_final_newline: false });
// => 'alert(1)'
// Only insert_final_newline is supported

Get file extensions list from a command like eslint . --fix --ext .js,.jsx:

const { getExtsFromCommand } = require('mrm-core');
getExtsFromCommand(`eslint . --fix --ext .js,.jsx`, 'ext');
// => ['js', 'jsx']
getExtsFromCommand(`prettier --write '**/*.js'`);
// => ['js']

Custom error class: `MrmError`

Use this class to notify user about expected errors in your tasks. It will be printed without a stack trace and will abort task.

const { MrmError } = require('mrm-core');
if (!fs.existsSync('.travis.yml')) {
  throw new MrmError('Run travis task first');
}

Changelog

The changelog can be found on the Releases page.

Contributing

Everyone is welcome to contribute. Please take a moment to review the contributing guidelines.

Authors and license

Artem Sapegin and contributors.

MIT License, see the included License.md file.

Current Tags

7.1.22 ... latest (a year ago)

mrm-core

Example

Installation

API

Work with files

JSON

YAML

INI

New line separated text files

Markdown

Plain text templates

Special files

package.json

File system helpers

Install and uninstall npm, Yarn, or pnpm packages

Utilities

Custom error class: MrmError

Changelog

Contributing

Authors and license

Current Tags

89 Versions

Custom error class: `MrmError`