index.js 1.2 KB

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  1. const registry = new Map();
  2. export function addDecoder(cases, importFn) {
  3. if (!Array.isArray(cases)) {
  4. cases = [cases]; // eslint-disable-line no-param-reassign
  5. }
  6. cases.forEach((c) => registry.set(c, importFn));
  7. }
  8. export async function getDecoder(fileDirectory) {
  9. const importFn = registry.get(fileDirectory.Compression);
  10. if (!importFn) {
  11. throw new Error(`Unknown compression method identifier: ${fileDirectory.Compression}`);
  12. }
  13. const Decoder = await importFn();
  14. return new Decoder(fileDirectory);
  15. }
  16. // Add default decoders to registry (end-user may override with other implementations)
  17. addDecoder([undefined, 1], () => import('./raw.js').then((m) => m.default));
  18. addDecoder(5, () => import('./lzw.js').then((m) => m.default));
  19. addDecoder(6, () => {
  20. throw new Error('old style JPEG compression is not supported.');
  21. });
  22. addDecoder(7, () => import('./jpeg.js').then((m) => m.default));
  23. addDecoder([8, 32946], () => import('./deflate.js').then((m) => m.default));
  24. addDecoder(32773, () => import('./packbits.js').then((m) => m.default));
  25. addDecoder(34887, () => import('./lerc.js').then((m) => m.default));
  26. addDecoder(50001, () => import('./webimage.js').then((m) => m.default));