psn-js/decoders/info/info-tracker-list-chunk.js

const Parser = require('binary-parser').Parser;

const infoTrackerNameParser = new Parser()
  .uint16le('id')
  .uint16le('data_len', {
    formatter: (item) => {
      const binary = item.toString(2).padStart(16, '0');
      return Number.parseInt(binary.substring(1), 2);
    },
  })
  .seek(-2)
  .uint16le('has_subchunks', {
    formatter: (item) => {
      const binary = item.toString(2).padStart(16, '0');
      return binary.charAt(0) === '1';
    },
  })
  .string('tracker_name', { length: 'data_len' });

const infoTrackerParser = new Parser()
  .uint16le('id')
  .uint16le('data_len', {
    formatter: (item) => {
      const binary = item.toString(2).padStart(16, '0');
      return Number.parseInt(binary.substring(1), 2);
    },
  })
  .seek(-2)
  .uint16le('has_subchunks', {
    formatter: (item) => {
      const binary = item.toString(2).padStart(16, '0');
      return binary.charAt(0) === '1';
    },
  })
  .nest('tracker_name', {
    type: infoTrackerNameParser,
  });

module.exports = new Parser().array('trackers', { type: infoTrackerParser, readUntil: 'eof' });