Add generateKey X25519 CryptoKeyPair

[anflext]

⚙ Compilation target

ES2023

⚙ Library

dom.generated.d.ts

Missing / Incorrect Definition

Need add generateKey X25519 algorithm CryptoKeyPair.
Now use below code with Property 'publicKey' does not exist on type 'CryptoKey | CryptoKeyPair' error:

const keyPair = await crypto.subtle.generateKey(
  {
    name: "X25519",
  },
  true,
  ["deriveKey"],
);

Sample Code

generateKey(algorithm: "X25519" | { name: "X25519" }, extractable: boolean, keyUsages: ReadonlyArray<"deriveBits" | "deriveKey">): Promise<CryptoKeyPair>;

Documentation Link

https://developer.mozilla.org/en-US/docs/Web/API/SubtleCrypto/generateKey

[MartinJohns]

That API is already added.

[anflext]

💯 OK. I hope soon I don't need hack the extension and node module code.

[MartinJohns]

There's neither a need to wait, nor to hack anything. You just need a better understanding of TypeScript. The method returns a value typed CryptoKey | CryptoKeyPair, because the method can either return a CryptoKey or a CryptoKeyPair. You seemingly try to access the property publicKey, which only exists on CryptoKeyPair, but not on CryptoKey.

You can use the instanceof operator to check if you're dealing with a CryptoKey or a CryptoKeyPair value: keyPair instanceof CryptoKey. What you do in your use-case when the case you get is a CryptoKey I don't know, perhaps throw an error?

Alternatively you can just use a type assertion, reducing the runtime overhead, but also decreasing safety: (keyPair as CryptoKeyPair).publicKey

Playground link

async function example() {
    const keyPair = await crypto.subtle.generateKey({ name: "X25519" }, true, ["deriveKey"]);

    if (keyPair instanceof CryptoKey) {
        throw new Error("Unexpected generateKey result. Expected CryptoKeyPair, got CryptoKey.");
    }

    const publicKey = keyPair.publicKey;
    return publicKey;
}

console.clear();
example().then(x => console.log('result', x));

[anflext]

👍 Excellent explain. I am a beginner of TypeScript. You code use implicit type convert. But my hack code learn from the source code of src/lib/dom.generated.d.ts. And I think like Ed25519 declare, if implicit declare X25519 the beginner will simply and smooth write code. That ONLY my simply suggest. That lowest change the normal JavaScriptcode. TypeScript is great that I used and I will learn more 🤝