index.js

/**
 * Module to parse commandline-args and options.
 * @author Muhammad Dadu
 * @module arghandle
 */
const _ = require('underscore');

(function (){
	/**
	 * @Constructor
	 * @param {object} options - defines the options for the argument parser
	 * @param {number} options.startIndex - index to start parsing arguments
	 * @param {array} options.argv - command line arguments from the system
	 * @param {array} options.definedArgs - an array of custom argument handlers
	 */
	function ArgHandle(options) {
		options = options || {};
		// create a index to store the itteration
		this.startIndex = options.startIndex || 2;
		// argv
		this.argv = options.argv || [];
		// create an array of args permitted
		this.definedArgs = options.definedArgs || [];
		
		// add default help args
		this.definedArgs.push({
			keys: ['--help', '-h'],
			method: function (self) {
				// log all the commands to the terminal [this.args]
				console.log("\nUsage: script <command> \n");
				console.log("Available commands:");
				for (var argObjectIndex in self.definedArgs) {
					var argObject = self.definedArgs[argObjectIndex];
					console.log(" -", argObject.description);
					console.log("    Usage: ", JSON.stringify(argObject.keys), "\n")
				};
				
			},
			description: 'This argument shows the list of arguments available'
		});
	}

	/**
	 * Concat custom argument handlers
	 * @param {array} argObjectArray - an array of custom argument handlers
	 */
	ArgHandle.prototype.concat = function (argObjectArray) {
		// append customArgs to array
		this.definedArgs = this.definedArgs.concat(argObjectArray);
	}

	/**
	 * Push custom argument handler
	 * @param {object} argObject - custom argument handler
	 */
	ArgHandle.prototype.push = function (argObject) {
		// append customArgs to array
		this.definedArgs.push(argObject);
	}

	/**
	 * Gets the next argument from argv
	 * @return {string} argument
	 */
	ArgHandle.prototype.getNext = function() {
		this.index++;
		return this.argv[this.index];
	}

	/**
	 * Starts to process the arguments and sent to the custom even handlers
	 * @param  {system.argv} argv - command line arguments from the system
	 * @return {bool} status of processing arguments [false == failure]
	 */
	ArgHandle.prototype.process = function (argv) {
		// store the arguments
		this.argv = argv || this.argv;
		// reset index
		this.index = this.startIndex;
		// Process enviromental variables
		for (var argl = this.argv.length; this.index < argl; this.index++) {
			var arg = this.argv[this.index],
				argObject = _.find(this.definedArgs, function (object) {
					if (object.keys.indexOf(arg) > -1) {
						return object;
					}
				});

			if (!argObject) {
				console.error('Undefined argument', arg);
				return false;
			}

			argObject.method.call(this, this);
		}
		return true;
	}

	// Node.js
	if (typeof module !== 'undefined' && module.exports) {
		module.exports = ArgHandle;
	}
	// AMD / RequireJS
	else if (typeof define !== 'undefined' && define.amd) {
		define([], function () {
			return ArgHandle;
		});
	}
	// included directly via <script> tag
	else {
		root.arghandle = ArgHandle;
	}
}());