Convert innerhtml to numbers and do calculations

Question

I'm making a simple material calculator but when I sum the values ​​I get 27002700 instead of 5400 So I tried pushing it to an array and using .map and Number, I rewrote it about 10 times. I'm out of ideas.

const heightValue = document.querySelector(".height-value")
const tottalDiv = document.querySelector(".tottal-div")

let heightArr = []
function rangeSlide2(value){
  heightValue.innerHTML = value;
}
heightArr.push(heightValue.innerHTML)
function tottal() {
 let tonum = heightArr.map(Number)
  tottalDiv.innerHTML = tonum + tonum;
}

<input type="range" name="range" id="height-range" min="2000" max="3500" step="100" value="2700" onchange="rangeSlide2(this.value)" onmousemove="rangeSlide2(this.value)">
        <span class="height-value">2700</span>
        
        <div class="button-div">
      <button type="button" class="submit" onclick="tottal()">tottal</button>
    </div>

    <div class="tottal-div">0</div>

Answer 1

The result of

map will be an array and when you try to add two arrays with one value it will be converted to string so [2700 ] [2700] Same as '2700' '2700' = '27002700'.

So, I think what you need is the reduce method to sum all values.

const heightValue = document.querySelector(".height-value")
const tottalDiv = document.querySelector(".tottal-div")

let heightArr = []
function rangeSlide2(value){
  heightValue.innerHTML = value;
}
heightArr.push(+heightValue.innerHTML)
function tottal() {
  let tonum = heightArr.reduce((acc, item) => acc + item)
  tottalDiv.innerHTML = tonum + tonum;
}

<input type="range" name="range" id="height-range" min="2000" max="3500" step="100" value="2700" onchange="rangeSlide2(this.value)" onmousemove="rangeSlide2(this.value)">
        <span class="height-value">2700</span>
        
        <div class="button-div">
      <button type="button" class="submit" onclick="tottal()">tottal</button>
    </div>

    <div class="tottal-div">0</div>