Simple `function( ... )` parser on JavaScript

var myString = "testFunction( initTask(arg1, arg2) + middlewareTask(arg3) + testEnv(arg6) )";
var Parser = (function(str) {

    var moreBrackets = function(part) {
        if (part.indexOf('(') != -1) {
            return true;
        } else {
            return false;
        }
    }

    var moreHard = function(part) {
        if (part.indexOf('+') != -1) {
            return true;
        } else {
            return false;
        }
    }

    var ArgsCheck = function(subpart) {
        if (subpart.indexOf(',') != -1) {
            return subpart
                .split(',')
                .map(function(rawArg){
                    return rawArg.trim();
                });
        } else {
            return subpart.trim();
        }
    }

    var nextCheck = function(part) {
        var workingSubParts = [];

        if (moreHard(part)) {
            workingSubParts = part
                .split('+')
                .map(function(item){ return item.trim(); });
        } else {
            if (moreBrackets(part)) {
                workingSubParts = [part];
            } else {
                workingSubParts = part;
            }
        }

        if (typeof(workingSubParts) == typeof([])) {
            return workingSubParts.map(function(parted){
                return common(parted);
            });
        } else {
            return ArgsCheck(workingSubParts);
        }
    }

    var common = function(part) {
        var tmpLevel   = 0;
        var inBrackets = 0;
        var key        = "";
        var value      = "";

        for (var i = 0; i < part.length; i++) {
            let char = part[i];

            if ( (char != '(') && (char != ')') ) {
                if (!inBrackets) {
                    key = key + char;
                } else {
                    value = value + char;
                }
            } else {
                if ( (!inBrackets) && (tmpLevel == 0) ) {
                    // dats first `(`
                    inBrackets = 1;
                    tmpLevel   = 1;
                } else {
                    if (char == '(')
                        tmpLevel += 1;
                    else {
                        tmpLevel -= 1;

                        if (tmpLevel == 0)
                            break;
                    }

                    value = value + char;
                }
            }
        }

        return [key.trim(), nextCheck(value.trim())];
    }

    return common(str);
})(myString);

console.log(myString);
console.dir(Parser);