Get Command Line Arguments in Node

getCommandLineArgumentsInNode.js

/* Example: Say you run this from the command line:
  
    node myscript.js -color blue -names joe jenny -month september
   
   You can get the arguments in your script by calling the following method as such:
   
    var color = getCmdLineArgument("-color")    //returns "blue"
    var names = getCmdLineArgument("-names", 2) //returns ["joe", "jenny"]
    var month = getCmdLineArgument("-month")    //returns "september"
    var ghost = getCmdLineArgument("-ghost")    //returns null
*/
function getCmdLineArgument(argument, numberOfValues=1){
    
    if(!numberOfValues || typeof(numberOfValues) != "number" || numberOfValues<1){
        throw "Invalid number of values";
    }

    if(argument == null){
        throw "Invalid argument"
    }
    
    var argIndex = process.argv.indexOf(argument);

    if(argIndex == -1){
        return null;
    }

    if(argIndex + numberOfValues > process.argv.length-1){
        throw "Number of values expected exceeds array size"
    }

    if(numberOfValues == 1){
        return process.argv[argIndex+numberOfValues];
    } else {
        return process.argv.slice(argIndex+1, argIndex+numberOfValues+1);
    }
}

/*
  Returns true if the argument was passed in from the command line.
  Example:
  From command line:
    node myscript.js --help
    
  In our script.js:
    var wantsHelp = hasCmdLineArgument("--help"); // returns true;
*/
function hasCmdLineArgument(argument){
    return process.argv.indexOf(argument) != -1;
}