"Meow" is a helper library for creating command-line interface (CLI) applications using JavaScript. It significantly simplifies the handling and parsing of command-line arguments. Apart from parsing arguments, Meow also converts flags to camel case, negates flags using the "--no-" prefix, and outputs versions and help text when "--version" and "--help" are used, respectively. Furthermore, it makes unhandled rejected promises fail hard, sets the process title to the binary name defined in the package.json, and remarkably does all this without any external dependencies, providing a lightweight solution for creating CLIs.
To use Meow, first, you have to install it through npm with the command npm install meow
. After installing, you can use it in your JS files. Below is an example of how to use Meow:
#!/usr/bin/env node
import meow from 'meow';
import foo from './lib/index.js';
const cli = meow(`
Usage
$ foo <input>
Options
--rainbow, -r Include a rainbow
Examples
$ foo unicorns --rainbow
π unicorns π
`, {
importMeta: import.meta,
flags: {
rainbow: {
type: 'boolean',
shortFlag: 'r'
}
}
});
foo(cli.input.at(0), cli.flags);
In this example, a command-line interface is created with the usage statement "foo <input>". It has an option "--rainbow" which can also be represented as "-r". The example shows how to call your application with the command ./foo-app.js unicorns --rainbow
.
The documentation for Meow can be found in its README content on its GitHub page, reachable at https://github.com/sindresorhus/meow. There, you will find comprehensive information about its features, installation process, usage examples, API specification, options, and other helpful resources for perfecting your command line tools.