Local cache of text() and arrayBuffer()

[lpatiny]

Currently each time we call the async function text() or arrayBuffer() the data are reloaded (refetch if it is coming from a web server).

We could therefore have an internal cache system.

One way would be to create a class CachedFileCollectionItem that is wrapping FileCollectionItem.

At first CachedFileCollectionItem would exactly contain the same properties / methods as FileCollectionItem. However we would change the method once the data has been fetched.

class CachedFileCollectionItem {
  constructor(fileCollectionItem) {
    this.fileCollectionItem = fileCollectionItem;
  }
  async text() {
    return this.textCache = this.textCache || this.fileCollectionItem.text();
  }
  async arrayBuffer() {
    return this.arrayBufferCache = this.arrayBufferCache || this.fileCollectionItem.arrayBufferCache();
  }
  async stream() {
    return this.fileCollectionItem.stream(); // no cache for stream !
  }
  get lastModified() {return this.fileCollectionItem.lastModified};
  get name() {return this.fileCollectionItem.name};
  get relativePath() {return this.fileCollectionItem.relativePath};
  get size() {return this.fileCollectionItem.size};

}

The files in FileCollection would therefore become an array of CachedFileCollectionItem
readonly files: CachedFileCollectionItem[];