Add to and from entropy methods to mnemonic primitive

packages/primitives/src/mnemonic.ts

@@ -1,8 +1,11 @@
 import {
   bip39WordListEnglish,
+  decodeBip39MnemonicNonStandard,
   deriveSeedFromBip39Mnemonic,
+  encodeBip39MnemonicNonStandard,
   generateBip39MnemonicNonStandard,
 } from '@bitauth/libauth';
+import { Bytes } from './bytes.js';
 
 export type MnemonicRaw = {
   words: string[];
@@ -61,6 +64,26 @@ export class Mnemonic {
       : this.fromPhrase(phraseOrWords, wordList);
   }
 
+  /**
+   * Instantiates a mnemonic from entropy.
+   *
+   * @param entropy The entropy to use to derive the mnemonic words.
+   * @param wordList Optional wordlist (defaults to English BIP-39 wordlist).
+   *
+   * @throws {Error} If mnemonic could not be generated.
+   *
+   * @returns Instance of Mnemonic.
+   */
+  public static fromEntropy(entropy: Uint8Array, wordList: Array<string> = bip39WordListEnglish) {
+    const mnemonic = encodeBip39MnemonicNonStandard(entropy, wordList);
+
+    if (typeof mnemonic === 'string') {
+      throw new Error(mnemonic);
+    }
+
+    return this.fromPhrase(mnemonic.phrase, wordList);
+  }
+
   /**
    * Instantiates a mnemonic from a string
    *
@@ -270,6 +293,25 @@ export class Mnemonic {
     return words;
   }
 
+  /**
+   * Returns the entropy for this mnemonic.
+   *
+   * @param wordList Optional wordlist (defaults to English BIP-39 wordlist).
+   *
+   * @throws {Error} If entropy could not be decoded from the mnemonic using the provided wordlist.
+   *
+   * @returns The entropy used to derive the mnemonic words.
+   */
+  public toEntropy(wordList: Array<string> = bip39WordListEnglish): Bytes {
+    const entropy = decodeBip39MnemonicNonStandard(this.toPhrase(), wordList);
+
+    if (typeof entropy === 'string') {
+      throw new Error(entropy);
+    }
+
+    return Bytes.fromBytes(entropy);
+  }
+
   /**
    * Returns a serializable represntation of the class
    *