WebAssembly / JS Binding¶

The WASM binding runs the nirs4all-formats sniffers and decoders in the browser or in Node, entirely from in-memory bytes. Parser logic stays in the Rust core; the binding only serialises records to plain JS objects.

Build & package¶

Built with wasm-pack:

wasm-pack build bindings/wasm --target web    --release                  # browser (ES modules)
wasm-pack build bindings/wasm --target nodejs --release --out-dir pkg-node  # Node / Bun

The output is the nirs4all-formats-wasm package: JS glue, the .wasm binary and generated TypeScript typings.

API¶

Function	Signature	Returns
`version()`	`() => string`	Crate version, e.g. `"0.1.0-alpha.1"`.
`features()`	`() => { hdf5: boolean, matlab: boolean, parquet: boolean }`	Which format features this bundle was compiled with.
`probeBytes(filename, bytes)`	`(string, Uint8Array) => Probe[]`	Ordered candidate readers (best first).
`openBytes(filename, bytes)`	`(string, Uint8Array) => SpectralRecord[]`	Decoded records (single-file formats).
`openWithSidecars(filename, bytes, sidecars)`	`(string, Uint8Array, Record<string, Uint8Array>) => SpectralRecord[]`	Decoded records for sidecar-bearing formats.

init() (the default export) must be awaited once before any call.

The filename argument is required because several sniffers disambiguate by extension (.lan, .spc, .hdr, …). Only the first 8 KB of bytes is used for probing; pass the whole buffer or just the head.

Shapes¶

Probe — { format, reader, confidence, reason }.
SpectralRecord — the same JSON shape as nirs4all-formats read-json: { signals, signal_type, targets, metadata, provenance, quality_flags }. See the data model. (JSON cannot represent NaN/Inf; use the native or Python path when signal values may be non-finite.)

Example¶

import init, { version, features, probeBytes, openBytes, openWithSidecars }
  from "nirs4all-formats-wasm";

await init();
console.log(version(), features());

const bytes = new Uint8Array(await file.arrayBuffer());
const candidates = probeBytes(file.name, bytes);

try {
  const records = openBytes(file.name, bytes);
  // ... use records[0].signals, .metadata, .provenance
} catch (err) {
  // Sidecar formats throw UnsupportedSidecar — supply companions instead:
  const records = openWithSidecars("cube.img", imgBytes, { "cube.hdr": hdrBytes });
}

Scope¶

The WASM build compiles fmt-hdf5, fmt-matlab and fmt-parquet on, so single-file HDF5/NetCDF payloads, MATLAB MAT / RData, Parquet tables and the HDF5-backed sidecar formats (FGI XML+HDF5, NetCDF MFRSR, Allotrope ADF) all decode in the browser. The core uses browser-compatible compression (lzma-rs for RData, snappy/zstd for Parquet) and a pure-Rust HDF5 stack, so no C dependency is needed. Check features() at runtime to confirm what a given bundle was compiled with.

Sidecar formats (ENVI Standard, ENVI SLI, AVIRIS/ERDAS LAN, FGI XML+HDF5, NetCDF MFRSR) return UnsupportedSidecar from openBytes; route them through openWithSidecars with a { name: Uint8Array } map of companion files.

Tests¶

node bindings/wasm/tests/smoke.js
node bindings/wasm/tests/sidecars.test.js