calculator

//popravi q dokato ne vuvede sledvasht znak,da chete numbers (789) go vzima v tozi sluchai kato 7 i 8


function solve() {
    let sum = 0;
    let firstNumber
    let secondNumber
    let operand = ""

    let operations = {
        "+": (firstNumber, secondNumber) => { return firstNumber + secondNumber },
        "-": (firstNumber, secondNumber) => { return firstNumber - secondNumber },
        "*": (firstNumber, secondNumber) => { return firstNumber * secondNumber },
        "/": (firstNumber, secondNumber) => { return firstNumber / secondNumber },
    }

    let expressionOutput = document.getElementById("expressionOutput")
    let resultOutput = document.getElementById("resultOutput")
    let clearButton=document.getElementsByClassName("clear")[0]
    clearButton.addEventListener("click",clear)



    Array.from(document.getElementsByClassName("keys")).map(x => x.addEventListener("click", function findResult(e) {
        let element = e.target.textContent

        if(element==="C"){
            clear()
        }


        if (element === "=") {
            resultOutput.textContent = operations[operand](firstNumber, secondNumber)
            operand=""
            firstNumber=NaN;
            secondNumber=NaN;


        } else {
            expressionOutput.textContent += element

            if ("0123456789".includes(element)) {
                if (operand==="") {
                    if(isNaN(firstNumber)){
                        firstNumber=0;
                        firstNumber += Number(element)
                    }else{
                        let str=firstNumber+""+element;
                        firstNumber=Number(str)
                    }

                } else {
                    if(isNaN(secondNumber)){
                        secondNumber=0;
                        secondNumber +=Number(element)
                    }else{
                        let str =secondNumber+""+element
                        secondNumber=Number(str)

                    }

                }


            }else if(element==="."){
                if(operand===""){
                    let str=firstNumber+"."
                    firstNumber=Number(str)
                }else{
                    let str=secondNumber+"."
                    secondNumber=Number(str)
                }

            } else if ("/ x - . +".includes(element)) {
                switch (element) {            //otdelen metod
                    case "/":
                        operand = "/"
                        break;
                    case "x":
                        operand = "*"
                        break;
                    case "-":
                        operand = "-"
                        break;
                    case "+":

                        operand = "+"

                        break;
                    //dobavi . operator

                }
            }
        }

    }))
    function clear(){
        resultOutput.textContent =""
        expressionOutput.textContent=""
    }


}