Method getHeader

js/src/index.ts:658–681

(source: Source)

  }

  async getHeader(source: Source): Promise<Header> {
    const cacheKey = source.getKey();
    const cacheValue = this.cache.get(cacheKey);
    if (cacheValue) {
      cacheValue.lastUsed = this.counter++;
      const data = cacheValue.data;
      return data as Header;
    }

    const res = await getHeaderAndRoot(source, this.decompress);
    if (res[1]) {
      this.cache.set(res[1][0], {
        lastUsed: this.counter++,
        data: res[1][2],
      });
    }

    this.cache.set(cacheKey, {
      lastUsed: this.counter++,
      data: res[0],
    });
    this.prune();
    return res[0];
  }

  async getDirectory(
    source: Source,