Class: Pool

The size of the pool. Defaults to the number of CPUs available. When this parameter is null or 0, then the decoding will be done in the main thread.

A function that creates the decoder worker. Defaults to a worker with all decoders that ship with geotiff.js. The createWorker() function is expected to return a Worker compatible with Web Workers. For code that runs in Node, web-worker is a good choice.

A worker that uses a custom lzw decoder would look like this my-custom-worker.js file:

import { addDecoder, getDecoder } from 'geotiff';
addDecoder(5, () => import ('./my-custom-lzw').then((m) => m.default));
self.addEventListener('message', async (e) => {
  const { id, fileDirectory, buffer } = e.data;
  const decoder = await getDecoder(fileDirectory);
  const decoded = await decoder.decode(fileDirectory, buffer);
  self.postMessage({ decoded, id }, [decoded]);
});

The way the above code is built into a worker by the createWorker() function depends on the used bundler. For most bundlers, something like this will work:

function createWorker() {
  return new Worker(new URL('./my-custom-worker.js', import.meta.url));
}