Parsing commandline arguments in JavaScript.

parsing_arguments_in_javascript.js

// Utility methods. Makes the code more readable.
Array.prototype.contains = function (element) {
    return (this.indexOf(element) !== -1);
}
String.prototype.hasPrefix = function (prefix) {
    return (this.lastIndexOf(prefix, 0) === 0);
}
 
    var parts = [ ], flags = [ ];
 
    // Tokenize.
    var re = /(?:”([^”]+)”|(\S+))/g;
    var matches;
    while ((matches = re.exec(enteredText)) !== null)
        parts.push(matches[1] || matches[2]);
   
    // Filter out and set aside flag-bearing tokens.
    let flagTokens = parts.filter(part => part.hasPrefix(″-”));
    parts = parts.filter(part => !part.hasPrefix(″-”));
   
    // Construct list of unique flags.
    flagTokens.forEach(token => {
        if (token.hasPrefix(″--”) && !flags.contains(token.substring(2)))
            flags.push(token.substring(2));
        else
            [...token.substring(1)].forEach(c => {
                if (!flags.contains(c)) flags.push(c);
            });
    });