`RuntimeError: unreachable` while using polkadot js to do sr25519 sign

Question

await cryptoWaitReady();

const json = JSON.parse(xxx);
const keyring = new Keyring({ ss58Format: 42 });
const pair = keyring.addFromPair(decoded, json.meta, 'sr25519');
// const pair = keyring.addFromUri('//Alice', null, 'sr25519');
const sig = pair.sign(..);

Everything works well if I use //Alice to sign. But if I use json key to sign then I got this error.

If I remove the await cryptoWaitReady(); I'll get The WASM interface has not been initialized..

Answer 1

Because the xxx is an ed25519 style key.

I shouldn't set it to sr25519.

And the runtime doesn't provide an interface to sign this; check https://github.com/polkadot-js/common/issues/929#issuecomment-813324953.