hpke-js/esm/src/kdfs/hkdfSha384.js

A Hybrid Public Key Encryption (HPKE) module for various JavaScript runtimes

import { HkdfSha384Native, hmac, sha384 } from "@hpke/common";
export class HkdfSha384 extends HkdfSha384Native {
    async extract(salt, ikm) {
        await this._setup();
        if (salt.byteLength === 0) {
            salt = new ArrayBuffer(this.hashSize);
        }
        if (salt.byteLength !== this.hashSize) {
            return hmac(sha384, new Uint8Array(salt), new Uint8Array(ikm))
                .buffer;
        }
        const key = await this._api.importKey("raw", salt, this.algHash, false, [
            "sign",
        ]);
        return await this._api.sign("HMAC", key, ikm);
    }
}