Convertisseur

<h2>Convertisseur de mesures :</h2>
    <div class="form-group">
        <label>km</label>
        <input id="km" type="number" placeholder="km">
    </div>
    <div class="form-group">
        <label>m</label>
        <input id="m" type="number" placeholder="m">
    </div>
    <div class="form-group">
        <label>dm</label>
        <input id="dm" type="number" placeholder="dm">
    </div>
    <div class="form-group">
        <label>cm</label>
        <input id="cm" type="number" placeholder="cm">
    </div>
    <div class="form-group">
        <label>mm</label>
        <input id="mm" type="number" placeholder="mm">
    </div>
    <div class="form-group">
        <label>mi</label>
        <input id="mi" type="number" placeholder="mi">
    </div>
    <div class="form-group">
        <label>pouces</label>
        <input id="inch" type="number" placeholder="pouces">
    </div>
    <div class="form-group">
        <label>ft</label>
        <input id="ft" type="number" placeholder="ft">
    </div>
    <div class="form-group">
        <label>yrd</label>
        <input id="yrd" type="number" placeholder="yrd">
    </div>

.form-group{
        display: inline-block;
        padding: 10px;
}

let km = document.getElementById("km");
let m = document.getElementById("m");
let dm = document.getElementById("dm");
let cm = document.getElementById("cm");
let mm = document.getElementById("mm");
let mi = document.getElementById("mi");
let inch = document.getElementById("inch");
let ft = document.getElementById("ft");
let yrd = document.getElementById("yrd");

km.addEventListener("input", function(){convMesures(this.id, this.value);});
m.addEventListener("input", function(){convMesures(this.id, this.value);});
dm.addEventListener("input", function(){convMesures(this.id, this.value);});
cm.addEventListener("input", function(){convMesures(this.id, this.value);});
mm.addEventListener("input", function(){convMesures(this.id, this.value);});
mi.addEventListener("input", function(){convMesures(this.id, this.value);});
inch.addEventListener("input", function(){convMesures(this.id, this.value);});
ft.addEventListener("input", function(){convMesures(this.id, this.value);});
yrd.addEventListener("input", function(){convMesures(this.id, this.value);});

function convMesures(id, valeur){
        if(id == "km"){
                m.value = valeur * 1000;
                dm.value = valeur * 10000;
                cm.value = valeur * 100000;
                mm.value = valeur * 1000000;
                mi.value = valeur * 0.62137119223733;
                inch.value = valeur * 39370.078740157;
                ft.value = valeur * 3280.8398950131;
                yrd.value = valeur * 1093.6132983377;
        }else if(id == "m"){
                km.value = valeur * 0.001;
                dm.value = valeur * 10;
                cm.value = valeur * 100;
                mm.value = valeur * 1000;
                mi.value = valeur * 0.00062137119223733;
                inch.value = valeur * 39.370078740157;
                ft.value = valeur * 3.2808398950131;
                yrd.value = valeur * 1.0936132983377;
        }else if(id == "dm"){
                km.value = valeur * 0.0001;
                m.value = valeur * 0.1;
                cm.value = valeur * 10;
                mm.value = valeur * 100;
                mi.value = valeur * 0.000062137119223733;
                inch.value = valeur * 3.9370078740157;
                ft.value = valeur * 0.32808398950131;
                yrd.value = valeur * 0.10936132983377;
        }else if(id == "cm"){
                km.value = valeur * 0.00001;
                m.value = valeur * 0.01;
                dm.value = valeur * 0.1;
                mm.value = valeur * 10;
                mi.value = valeur * 0.0000062137119223733;
                inch.value = valeur * 0.39370078740157;
                ft.value = valeur * 0.032808398950131;
                yrd.value = valeur * 0.010936132983377;
        }else if(id == "mm"){
                km.value = valeur * 0.000001;
                m.value = valeur * 0.001;
                dm.value = valeur * 0.01;
                cm.value = valeur * 0.1;
                mi.value = valeur * 0.00000062137119223733;
                inch.value = valeur * 0.039370078740157;
                ft.value = valeur * 0.0032808398950131;
                yrd.value = valeur * 0.0010936132983377;
        }else if(id == "mi"){
                km.value = valeur * 1.609344;
                m.value = valeur * 1609.344;
                dm.value = valeur * 16093.44;
                cm.value = valeur * 160934.4;
                mm.value = valeur * 1609344;
                inch.value = valeur * 63360;
                ft.value = valeur * 5280;
                yrd.value = valeur * 1760;
        }else if(id == "inch"){
                km.value = valeur * 0.0000254;
                m.value = valeur * 0.0254;
                dm.value = valeur * 0.254;
                cm.value = valeur * 2.54;
                mm.value = valeur * 25.4;
                mi.value = valeur * 0.000015782828282828;
                ft.value = valeur * 0.083333333333333;
                yrd.value = valeur * 0.027777777777778;
        }else if(id == "ft"){
                km.value = valeur * 0.0003048;
                m.value = valeur * 0.3048;
                dm.value = valeur * 3.048;
                cm.value = valeur * 30.48;
                mm.value = valeur * 304.8;
                mi.value = valeur * 0.00018939393939394;
                inch.value = valeur * 12;
                yrd.value = valeur * 0.33333333333334;
        }else if(id == "yrd"){
                km.value = valeur * 0.0009144;
                m.value = valeur * 0.9144;
                dm.value = valeur * 9.144;
                cm.value = valeur * 91.44;
                mm.value = valeur * 914.4;
                mi.value = valeur * 0.00056818181818181;
                inch.value = valeur * 36;
                ft.value = valeur * 3;
        }
}