X Expression

function xExpression(expression) {

    let index = 0;
    let symbol = expression[index];
    let rezult = 0;
    let expressionOperator = '+';

    while (symbol != '=') {
        if (symbol == '(') {
            let innerResult = 0.0;
            let innerOperator = '+';
            symbol = expression[++index];

            while (symbol != ')') {
                if (0 <= symbol - '0' && symbol - '0' <= 9) {
                    switch (innerOperator) {
                        case '+':
                            innerResult += symbol - '0';
                            break;
                        case '-':
                            innerResult -= symbol - '0';
                            break;
                        case '/':
                            innerResult /= symbol - '0';
                            break;
                        case '*':
                            innerResult *= symbol - '0';
                            break;
                        default:
                            break;
                    }
                } else if (symbol == '+' || symbol == '-' || symbol == '/' || symbol == '*') {
                    innerOperator = symbol;
                }
                symbol = expression[++index];
            }

            switch (expressionOperator) {
                case '+':
                    rezult += innerResult;
                    break;
                case '-':
                    rezult -= innerResult;
                    break;
                case '/':
                    rezult /= innerResult;
                    break;
                case '*':
                    rezult *= innerResult;
                    break;
                default:
                    break;
            }
        } else if (0 <= symbol - '0' && symbol - '0' <= 9) {
            switch (expressionOperator) {
                case '+':
                    rezult += symbol - '0';
                    break;
                case '-':
                    rezult -= symbol - '0';
                    break;
                case '/':
                    rezult /= symbol - '0';
                    break;
                case '*':
                    rezult *= symbol - '0';
                    break;
                default:
                    break;
            }
        } else if (symbol == '+' || symbol == '-' || symbol == '/' || symbol == '*') {
            expressionOperator = symbol;
        }
        symbol = expression[++index];
    }

    console.log(rezult.toFixed(2));
}

//Time limit in Judge 0/100

xExpression("4+6/5+(4*9-8)/7*2=");
xExpression("3+(6/5)+(2*3/7)*7/2*(9/4+4*1)=");