@digitalbazaar/vc-bitstring-status-list/lib/BitstringStatusList.js

Verifiable Credentials Bitstring Status List

/*!
 * Copyright (c) 2024 Digital Bazaar, Inc. All rights reserved.
 */
import {Bitstring} from '@digitalbazaar/bitstring';

export class BitstringStatusList {
  constructor({length, buffer} = {}) {
    this.bitstring = new Bitstring({length, buffer});
    this.length = this.bitstring.length;
  }

  setStatus(index, status) {
    if(typeof status !== 'boolean') {
      throw new TypeError('"status" must be a boolean.');
    }
    return this.bitstring.set(index, status);
  }

  getStatus(index) {
    return this.bitstring.get(index);
  }

  async encode() {
    return 'u' + await this.bitstring.encodeBits();
  }

  static async decode({encodedList}) {
    try {
      if(encodedList[0] !== 'u') {
        throw '"encodedList" must start with the character "u".';
      }
      const buffer = await Bitstring.decodeBits({
        encoded: encodedList.slice(1)
      });
      return new BitstringStatusList({buffer});
    } catch(e) {
      if(e instanceof Error) {
        throw e;
      }
      throw new Error(
        `Could not decode encoded status list; reason: ${e}`);
    }
  }
}