I got a js bundle.js

<script src="./bundle.js"></script>
<script>
    console.log(MyCrypto)
    let SpecParams = {   //初始值
        cureveName: 'p256',
        signHashType: 'SHA-384'
    }
    let MyCrypto = MyCrypto.default
    let eccEnde = new MyCrypto.EccCrypto(SpecParams);
    function getKeyPair() {
        let keyJson = eccEnde.generateKeypair();
        return keyJson
    }
 </script>

and there are many other functions in this bundle.js like sign、verify、encrypt、decrypt

how could I use these js function in fluter android app