Monorepo stuff

Signed-off-by: James Zuccon <zuccon@gmail.com>

packages/primitives/src/hd-public-node.ts

@@ -0,0 +1,112 @@
+import { PublicKey } from './public-key.js';
+
+import {
+  encodeHdPublicKey,
+  decodeHdPublicKey,
+  deriveHdPath,
+} from '@bitauth/libauth';
+
+import type {
+  DecodedHdKey,
+  HdKeyNetwork,
+  HdPublicNodeValid,
+} from '@bitauth/libauth';
+
+/**
+ * Hierarchically Deterministic Public Node Entity.
+ */
+export class HDPublicNode {
+  // The HD Public Node.
+  public readonly node: HdPublicNodeValid;
+
+  /**
+   * Construct a new HD Public Node.
+   *
+   * @param node {HdPublicNode} The HD Public Node.
+   */
+  constructor(node: HdPublicNodeValid) {
+    this.node = node;
+  }
+
+  /**
+   * Creates a HD Public Node from the given XPriv Key.
+   *
+   * @param xpub {string} The XPriv Key.
+   *
+   * @throws {Error} If HD Public Node cannot be created.
+   *
+   * @returns {HDPrivateNode} The created HD Public Node.
+   */
+  public static fromXPub(xpub: string): HDPublicNode {
+    // Attempt to decode the XPub Key.
+    const decodeResult = decodeHdPublicKey(xpub);
+
+    // If a string is returned, this indicates an error...
+    if (typeof decodeResult === 'string') {
+      throw new Error(decodeResult);
+    }
+
+    // Return a new HD Public Node from the given XPub.
+    return new HDPublicNode(decodeResult.node);
+  }
+
+  /**
+   * Returns the XPub string for this node.
+   *
+   * @returns {string} The XPub string for this node.
+   */
+  public toString(): string {
+    // Return the Mainnet XPub.
+    return this.toXPub();
+  }
+
+  /**
+   * Gets the Public Key Entity for this node.
+   *
+   * @returns {PublicKey} The Public Key Entity for this node.
+   */
+  public publicKey(): PublicKey {
+    // Return a Public Key Entity from the public key of our node.
+    return new PublicKey(this.node.publicKey);
+  }
+
+  /**
+   * Derives a HD Public Node from the given BIP32 path.
+   *
+   * @param path {string} The BIP32 Path (e.g. m/44'/145'/0'/0/1).
+   *
+   * @throws {Error} If HD Public Node cannot be derived.
+   *
+   * @returns {HDPrivateNode} The derived HD Public Node
+   */
+  public derivePath(path: string): HDPublicNode {
+    // Attempt to derive the given path.
+    const derivePathResult = deriveHdPath(this.node, path);
+
+    // If a string is returned, this indicates an error...
+    if (typeof derivePathResult === 'string') {
+      throw new Error(derivePathResult);
+    }
+
+    // Return a new HD Public Node Entity derived from the given path.
+    return new HDPublicNode(derivePathResult);
+  }
+
+  /**
+   * Converts this node to an XPub Key for export.
+   *
+   * @param network {HdKeyNetwork} The network to encode for.
+   *
+   * @returns {string} The XPub Key.
+   */
+  public toXPub(network: HdKeyNetwork = 'mainnet'): string {
+    // Create our node info structure.
+    const nodeInfo = {
+      network: network,
+      node: this.node,
+    } as DecodedHdKey<HdPublicNodeValid>;
+
+    // Encode the XPub from our node info.
+    return encodeHdPublicKey(nodeInfo).hdPublicKey;
+  }
+}