ethers.js/src.ts/wordlists/wordlist-owl.ts
2022-11-27 21:45:42 -05:00

72 lines
2.1 KiB
TypeScript

// Use the encode-latin.js script to create the necessary
// data files to be consumed by this class
import { id } from "../hash/index.js";
import { assertArgument } from "../utils/index.js";
import { decodeOwl } from "./decode-owl.js";
import { Wordlist } from "./wordlist.js";
/**
* An OWL format Wordlist is an encoding method that exploits
* the general locality of alphabetically sorted words to
* achieve a simple but effective means of compression.
*
* This class is generally not useful to most developers as
* it is used mainly internally to keep Wordlists for languages
* based on ASCII-7 small.
*
* If necessary, there are tools within the ``generation/`` folder
* to create these necessary data.
*/
export class WordlistOwl extends Wordlist {
#data: string;
#checksum: string;
/**
* Creates a new Wordlist for %%locale%% using the OWL %%data%%
* and validated against the %%checksum%%.
*/
constructor(locale: string, data: string, checksum: string) {
super(locale);
this.#data = data;
this.#checksum = checksum;
this.#words = null;
}
get _data(): string { return this.#data; }
_decodeWords(): Array<string> {
return decodeOwl(this.#data);
}
#words: null | Array<string>;
#loadWords(): Array<string> {
if (this.#words == null) {
const words = this._decodeWords();
// Verify the computed list matches the official list
const checksum = id(words.join("\n") + "\n");
/* c8 ignore start */
if (checksum !== this.#checksum) {
throw new Error(`BIP39 Wordlist for ${ this.locale } FAILED`);
}
/* c8 ignore stop */
this.#words = words;
}
return this.#words;
}
getWord(index: number): string {
const words = this.#loadWords();
assertArgument(index >= 0 && index < words.length, `invalid word index: ${ index }`, "index", index);
return words[index];
}
getWordIndex(word: string): number {
return this.#loadWords().indexOf(word);
}
}