Javascript object undefined error, even though the object is clearly defined

I’ve been trying to build up a website that involves dropdown lists, and following are the html code and js code

`<!DOCTYPE html>
<body id = "bdprod">
    <div class = "combo">
        <select id = 'sizes' onchange="enableGauge()">
            <option selected >select the size</option>
            <option id = "s12" >12 x 12</option>
            <option id = "s14">14 x 14</option>
            <option id = "s16">16 x 16</option>
            <option id = "s18">18 x 18</option>
            <option id = "s20">20 x 20</option>
            <option id = "s24">24 x 24</option>
        </select>
        <select id = 'gauge' disabled onchange="enableGauge()">
            <option selected >select the gauge</option>
            <option id = "g300">300 Gauge</option>
            <option id = "g350">350 Gauge</option>
        </select>
    </div>
    Price: <label id = "priceLabel">pricedisplay</label>

<script src = "cmgrowbags.js" type = "text/javascript"></script>
</body>
</html>

JS code

const prices = {
    "12×12 , 350 gauge": 20,
    "14×14 , 300 gauge": 24,
    "14×14 , 350 gauge": 26,
    "16×16 , 300 gauge": 27,
    "16×16 , 350 gauge": 30,
    "18×18 , 300 gauge": 34,
    "18×18 , 350 gauge": 36,
    "20×20 , 300 gauge": 42,
    "20×20 , 350 gauge": 46,
    "24×24 , 350 gauge": 62
};

function enableGauge() {
    const sizesSelect = document.getElementById("sizes");
    const gaugeSelect = document.getElementById("gauge");
    const priceLabel = document.getElementById("priceLabel");

    gaugeSelect.disabled = (sizesSelect.value === "select the size");
    priceLabel.innerHTML = ""; // Clear the price label

    if (sizesSelect.value !== "select the size" && gaugeSelect.value !== "select the gauge") {
            const size = sizesSelect.options[sizesSelect.selectedIndex].text;
            const gauge = gaugeSelect.options[gaugeSelect.selectedIndex].text;
            const key = `${size} , ${gauge}`;
            alert(key); //upto this part it works
            let price = prices[key];
                        priceLabel.innerHTML = `Price: ${price}`;
  }
}

upto the “alert(key)” statement it works but then the price variable doesn’t work and it just displays the price is undefined. help me pls