AutoCLI

This is alpha stage software, feedback welcome

When building CLIs for testing and admin of my code I often found that I had to repeat a lot of code. More importantly, I found that I wrote roughly the same texts both in JS Docs as in the help output of CLI commands.

AutoCLI is a small library with single function call that will generate a complete CLI for your Node.js project. It just needs to know what source files it should parse for JSDoc, and it will use that to build a model for what commands (functions) can be called, their names, description and accepted parameters. AutoCLI only works if your source code uses proper JS Doc!

Similar to: Python Fire, Python Typer

How it works

Using the excellent jsdoc-api package we can scan Javascript source files for JS Doc comments. Let's say you have this function:

// math.js
/**
 *	Adds two numbers.
 *
 * @param {number} a first number
 * @param {number} b second number
 * @returns {number}
 */
exports.adder = function (a, b) {
    return a+b;
}

Let's say your entry point script is:

// index.js
const { autoCLI } = require('node-autocli');

if (require.main === module) {
    await autoCLI(process.argv, 'math.js');
}

If you call node index.js adder <a> <b> it will run the function and output the result, or if you type something wrong, it will give you a help screen.

Features

• Generates a nice-looking automated help and version commands that lists all commands, plus top-level CLI information like description and version pulled from your package.json
• Prints help and parameters, including type and defaults, for individual commands
• Can handle a flat list of commands or commands nested into command groups
• Tries to guess which command the user intended if it can't find what was typed
• Can be provided an object of internal arguments that will be populated in code and not exposed to CLI users, so that you don't need to maintain different versions of your function
• Can take arguments as JSON encoded text or path to a JSON file
• If provided JSON is an array, it will run the command for each element, so it becomes a simple batch runner for commands

Planned features

• Automatically convert input arguments to correct type using JS Dcc parameter types
• Better error messages for improper JS Doc
• Fall back on parsing function signatures if no JS Doc available
• JSON from stdin
• Return a list of promises
• Utilize environment variables
• Correctly return exit codes
• BASH completions

Documentation

/**
 * Automatically generates a CLI for given sourcePaths with exported and
 * documented functions. Executes the command and options provided via the argv
 * array.
 *
 * @param {string[]} argv array of command options from `process.argv` 
 * @param {string|string[]|object} sourcePaths path(s) of source files to scan.
 * If an object, each key will denote a group of commands.
 * @param {object} [options={}] the options object
 * @param {string} options.cliName name of the CLI app to display when printing
 * help. Defaults to package.json values from calling module.
 * @param {string} options.cliDescription description of the CLI app to display
 * when printing help. Defaults to package.json values from calling module.
 * @param {string} options.cliVersion version of the CLI app to display when
 * printing help. Defaults to package.json values from calling module.
 * @param {object} options.minimistOpts specific options to minimist that is
 * used to parse command arguments
 * @param {object} options.internalArgs function parameters that should not be
 * exposed in CLI commands but instead populated internally
 * @param {boolean} [options.parallelize=true] if given multiple commands (with
 * -j), run them in parallel
 * @returns {Promise<any[]>} resolving to an array of command return values
 */