Comprehensive guide for building Node.js command-line interfaces using Commander.js. Use when creating CLI tools with options, commands, subcommands, arguments, and help system customization.
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This skill provides guidance for building Node.js command-line interfaces using Commander.js. It covers common patterns for defining options, commands, arguments, and customizing the help system.
npm install commander
const { program } = require('commander');
program
.option('-p, --port <number>', 'server port number')
.option('-d, --debug', 'output extra debugging')
.argument('<input>', 'input file to process')
.action((input, options) => {
console.log(`Processing ${input} on port ${options.port}`);
if (options.debug) console.log('Debug mode enabled');
});
program.parse();
const { Command } = require('commander');
const program = new Command();
program
.name('my-cli')
.description('CLI tool for managing tasks')
.version('1.0.0');
program.command('add')
.description('Add a new task')
.argument('<task>', 'task description')
.action((task) => {
console.log(`Added task: ${task}`);
});
program.command('list')
.description('List all tasks')
.action(() => {
console.log('Listing tasks...');
});
program.parse();
program.option('-d, --debug', 'enable debug mode');
// Usage: my-cli --debug
program.option('-p, --port <number>', 'server port');
// Usage: my-cli --port 8080
program.requiredOption('-k, --key <api-key>', 'API key is required');
// Usage: my-cli --key abc123
program.option('-f, --files <files...>', 'files to process');
// Usage: my-cli --file file1.txt file2.txt file3.txt
program.option('--no-cache', 'disable caching');
// Usage: my-cli --no-cache
program.option('-p, --port <number>', 'server port', 3000);
// Default: 3000 if not specified
function parsePort(value) {
const port = parseInt(value, 10);
if (isNaN(port)) {
throw new commander.InvalidArgumentError('Not a number.');
}
return port;
}
program.option('-p, --port <number>', 'server port', parsePort);
program.command('clone <source> [destination]')
.description('clone a repository')
.action((source, destination) => {
console.log(`Cloning ${source} to ${destination}`);
});
program.command('install [package-names...]', 'install one or more packages');
program.command('search [query]', 'search with optional query');
program.argument('<username>', 'user to login');
program.argument('[password]', 'password for user', 'no password given');
program.argument('<files...>', 'files to process');
program.arguments('<username> <password>');
program.addHelpText('after', `
Example call:
$ my-cli --help`);
program.helpOption('-e, --HELP', 'read more information');
program.showHelpAfterError();
// or
program.showHelpAfterError('(add --help for additional information)');
program
.option('-t, --trace', 'display trace statements')
.hook('preAction', (thisCommand, actionCommand) => {
if (thisCommand.opts().trace) {
console.log(`About to call: ${actionCommand.name()}`);
}
});
// Only look for program options before subcommands
program.enablePositionalOptions();
// Pass options through to another program
program.passThroughOptions();
// Allow unknown options
program.allowUnknownOption();
// Allow excess arguments
program.allowExcessArguments();
// Display custom error
program.error('Password must be longer than four characters');
// Override exit handling
program.exitOverride();
try {
program.parse(process.argv);
} catch (err) {
// custom processing
}
import { Command } from '@commander-js/extra-typings';
const program = new Command();
For comprehensive API documentation including all options, commands, arguments, help system customization, and advanced features, see the detailed API reference:
This reference includes:
This skill includes detailed API documentation:
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