Parse command line arguments in Node.js

There are many libraries to build CLI tools for Node.js like optimist, minimist, yargs, Caporal.js and commander to name just a few. In the following article Benny gives you an overview of his favorites.

Contents

• Code samples
• More Features

Code samples

My favorite CLI builder is commander because it comes with TypeScript definitions:

#!/usr/bin/env node
 
import program from 'commander';
 
const pkg = require('../package.json');
const appName = Object.keys(pkg.bin)[0];
 
program
  .description(pkg.description)
  .name(appName)
  .option('-c, --config <path>', 'set path to configuration file')
  .version(pkg.version)
  .parse(process.argv);
 
console.log('Configuration path', program.config);

Biggest lack of commander.js is that it does not fail if you have mandatory arguments but don't supply any argument at all. For example, it fails when calling node program.js -c because there is no value for c but it doesn't fail when just calling node program.js. Tested with commander v2.19.0. GitHub issue.

Luckily, Caporal.js addresses this issue:

#!/usr/bin/env node
 
import program from 'caporal';
 
const pkg = require('../package.json');
const appName = Object.keys(pkg.bin)[0];
 
program
  .version(pkg.version)
  .description(pkg.description)
  .name(appName)
  .option('--config <config>', 'set path to configuration file', undefined, undefined, true)
  .action((args, options, logger) => {
    logger.info(`Configuration value: ${options.config}`);
  });
 
program.parse(process.argv);

Should you just care about getting arguments, you will be good with minimist:

import * as minimist from 'minimist';
 
const argv = minimist(process.argv.slice(1));

More Features

• If you want to equip your program with some kind of configuration file (à la webpack.config.js or .babelrc) I can recommend cosmiconfig to you. Cosmiconfig searches for and loads configuration files with the extensions .json, .yaml, .yml, or .js.
• If you need pattern matching you will probably fall in love with Globs which are implemened by minimatch.
• If you need an interactive command line user interface with prompts, try Inquirer.js.
• For more colorful log messages on the terminal, there is chalk.