再次加载输入时清除结果显示

Question

在这里，在加载结果并尝试输入下一个输入后，它只会附加结果，但应清除显示以进行第二次计算。任何帮助将不胜感激。

var arr=[];
var input=0;

function numberBtn(arg){
    if ( document.getElementById("currentValue").innerHTML ==="ERROR" || (document.getElementById("currentValue").innerHTML == "0"))
    {
        document.getElementById("currentValue").innerHTML = "";
    }

    input += arg;
    document.getElementById("currentValue").innerHTML += arg;   
}

function calculate(val){
    if(input !== 0){
        addToArr(input); 
    }

    var answer = val[0];           
    var divideZero =0;
    var i=2

    switch(arr[i-1]){
        case '+':
            answer= Number(val[i-2]) + Number(val[i]);
            break;
        case '-':
            answer-= val[i];
            break;
        case '/':
            if (val[i] == 0) divideZero = 1;
            else answer = answer / val[i];
            break;
        case'*': 
            //console.log(value,'before multiply');
            answer = answer * val[i];
            // console.log(val[i],'after multiply');
            break;
        case'%':
            if (val[i] == 0) divideZero = 1;
            else{
                var q= val[i-2]/val[i];
                answer= val[i-2] - (val[i] * Math.floor(q));
            }
            break;
        case'+/-':
            answer= -answer;
            break;      
    }

    if ( divideZero === 1) { 
        clearAll();
        document.getElementById("currentValue").innerHTML = "ERROR";
    }
    else
    {
        document.getElementById("currentValue").innerHTML = answer;
        input = answer;
        arr = [];
    } 
}

function addToArr(input){
    arr.push(input);
}

function clearAll() {
    arr = [];
    input = 0;
    document.getElementById("currentValue").innerHTML = "0";
}

function operatorBtn(arg){
    if (input !== 0) {
        addToArr(input);
        addToArr(arg);
        document.getElementById("currentValue").innerHTML +=arg;
        input = 0;
    }
}