Exams - Listy (alternative solution)

function solve(args) {
    var defFunctions = {};
    for (var row = 0; row < args.length; row += 1) {
        var keyName, keyValue, command = '';
        var currentRow = args[row].trim();
        currentRow = currentRow.split('[').filter(Boolean);
        var leftPart = '', rightPart = '';
        if (currentRow.length == 1) {
            rightPart = currentRow[0].trim();
        } else {
            leftPart = currentRow[0].trim();
            rightPart = currentRow[1].trim();
        }

        if (leftPart.length) {
            leftPart = leftPart.split(/\s+/).filter(Boolean);
            if (leftPart.length === 1 && row == args.length - 1 && leftPart[0] != 'def') {
                command = leftPart[0];
            } else if (leftPart.length === 2 && leftPart[0] === 'def') {
                keyName = leftPart[1];
            } else if (leftPart.length === 3) {
                keyName = leftPart[1];
                command = leftPart[2];
            }
        }

        if (rightPart.length) {
            var params = rightPart.split(/[\], ]+/).filter(Boolean);
            params = parsingFunctionArguments(params, defFunctions);

            if (params.length > 1) {
                keyValue = calculateFuncCommandValue(params, command);
            } else {
                keyValue = params[0];
            }
        }

        if (row < args.length - 1 && !(keyName in defFunctions) && keyValue != undefined) {
            defFunctions[keyName] = keyValue;
        } else if (row === args.length - 1 && keyValue != undefined) {
            return keyValue
        }
    }

    function parsingFunctionArguments(strArr, object) {
        var argumsArr = [];
        for (var i = 0; i < strArr.length; i += 1) {
            if (isFinite(strArr[i])) {
                argumsArr.push(Number(params[i]));
            } else if (object.hasOwnProperty(params[i])) {
                var temp = object[params[i]];
                if (temp instanceof Array) {
                    Array.prototype.push.apply(argumsArr, temp);
                } else {
                    argumsArr.push(temp);
                }
            }
        }

        return argumsArr;
    }

    function calculateFuncCommandValue(paramsList, command) {
        switch (command) {
            case 'min':
                return Math.min.apply(null, paramsList);
            case 'max':
                return Math.max.apply(null, paramsList);
            case 'sum':
                var sum = 0;
                for (var i = 0; i < paramsList.length; i += 1) {
                    sum += paramsList[i];
                }
                return sum;
            case 'avg':
                sum = 0;
                for (i = 0; i < paramsList.length; i += 1) {
                    sum += paramsList[i];
                }
                return parseInt((sum / paramsList.length));
            default:
                return paramsList;
        }
    }
}

console.log(solve([
    'def func sum[5, 3, 7, 2, 6, 3]',
    'def func2 [5, 3, 7, 2, 6, 3]',
    'def func3 min[func2]',
    'def func4 max[5, 3, 7, 2, 6, 3]',
    'def func5 avg[5, 3, 7, 2, 6, 3]',
    'def func6 sum[func2, func3, func4 ]',
    'sum[func6, func4]'
]));

console.log(solve([
    'def func sum[1, 2, 3, -6]',
    'def newList [func, 10, 1]',
    'def newFunc sum[func, 100, newList]',
    '[newFunc]'
]));

console.log(solve([
    'def maxy max[100]',
    'def summary [0]',
    'combo [maxy, maxy,maxy,maxy, 5,6]',
    'summary sum[combo, maxy, -18000]',
    'def pe6o avg[summary,maxy]',
    'sum[7, pe6o]'
]));

console.log(solve([
    'def maxy max[100, 5000, 4,2,1]',
    'def summary1 [0]',
    'def summary11 avg[summary1,maxy]',
    'def summary111 avg[   summary11 ,  maxy]',
    'def summary1111 avg[summary111 , maxy]',
    'sum[75468, summary1111]'
]));