Parse and validate CLI arguments
A basic command looks like this:
// cmd.js
var Args = require('stdarg')
var number = require('stdopt/builtin/number')
var string = require('stdarg/string')
var command = new Args()
command.use(['port', 'p'], 'Server port', number)
command.use(['message', '-m'], 'Welcome message', string)
command.use(['log', 'l'], 'Toggle logging')
var argv = process.argv.slice(2)
var opts = command.parse(argv)
console.log('Parsed options: ' + JSON.stringify(opts))
console.log('Remaining argv: ' + argv.join(', '))You can invoke it like so:
$ node cmd.js argument --message "Hello, world" some more
Parsed options: {"message": "Hello, world"}
Remaining argv: argument, some, more
$ node cmd.js --port 80 --log some more arguments
Parsed options: {"port": 80, "log": true}
Remaining argv: some, more, arguments
$ node cmd.js -lp 80 some more arguments
Parsed options: {"port": 80, "log": true}
Remaining argv: some, more, arguments
$ node cmd.js --port stuff
Error: stuff is an invalid value for --port
$ node cmd.js --message
Error: undefined is an invalid value for --message
You can also generate help output based on the configured options. Given the command above, you can add this as follows:
args.use(['help', 'h'], 'Get help')
var argv = process argv.slice(2)
var opts = args.parse(argv)
if (opts.help) {
args.help().forEach(line => console.log(line))
}Invoking this gives the following output:
$ node cmd.js --help
--port, -p Server port
--message, -m Welcome message
--log, -l Toggle logging
--help, -h Get help
Apache-2.0