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Examples

The repository’s examples/ directory contains four self-contained applications. Each has its own package.json and README. Clone the repo, cd into one, and follow its README.

Opens a FITS file from disk, lists its HDUs, and prints a small cutout from the primary HDU. Ships its own copy of an HST/FOS multi-extension file, so it runs without arguments. Pass a path to point it at your own file.

Covers: NodeFileReader.open, openFits, readImage with a region.

Points HttpRangeReader at a FITS file on the NASA FITS Support Office’s public sample tree, enumerates HDUs, and reads a cutout from the first 2D image HDU. Only the byte ranges those calls need cross the network.

Covers: HttpRangeReader, lazy enumeration over HTTP, cutouts from a remote file.

A file picker in the browser. Wraps the picked File in a BlobReader, lists HDUs, and prints cutout values to the page. Vite serves it in dev mode.

Covers: BlobReader, openFits and readImage in the browser.

A file picker that renders the first 2D image HDU to a canvas as 8-bit grayscale, with a percentile stretch and the FITS Y-flip. The landing page of this site renders the Horsehead with the same approach.

Covers: full-image decode, display scaling, canvas rendering in user code.

The Node examples build with tsc and run as plain scripts. From inside an example directory:

Terminal window
pnpm install
pnpm build && node dist/main.js

The browser examples use Vite:

Terminal window
pnpm install
pnpm dev

CI builds and lints every example on each PR, so they stay current against the API. Running them is manual.