JSPM – zarrita@0.0.0

Package Exports

zarrita
zarrita/fsstore

Readme

Here be dragons (in JavaScript). Zarrita.js is a minimal, exploratory implementation of the Zarr version 3.0 core protocol. This repo is meant to mirror zarrita, the python implementation. The test suite in index.test.js mirrors the doctest from zarrita, and tests both the default MemoryStore and Node.js-specific FileSystemStore (located in ./fsstore.js).

NOTE: Only hierarchy creation and traversal are implemented. Need to implement get and set for ZarrArray, but currently arr.get_chunk(chunk_coord) is supported.

TODO:

Write minimal NDArray for slicing / indexing of ZarrArray.
Modularize lib. Bundle smallest core lib for travsersing hierarchy and decoding array chunks by key -- no ZarrArray indexing or NDArray. Top-level export mutates ZarrArray prototype and adds indexing and NDArray dep.

import FileSystemStore from './fsstore.js';
import { create_hierarchy, registry } from './zarrita.js';
import GZip from 'numcodecs/gzip';

// codec registry is empty by default, so must add codecs
registry.set(GZip.codecId, () => GZip);

// Clean slate
import fs from 'fs';
fs.rmdirSync('test.zr3', { recursive: true });

// Create store
const store = new FileSystemStore('test.zr3');

(async () => {
  // Create hierarchy
  const h = await create_hierarchy(store);

  // Create Array
  await h.create_array('/arthur/dent', {
    shape: [5, 10],
    dtype: '<i4',
    chunk_shape: [2, 5],
    compressor: new GZip(1),
    attrs: { question: 'life', answer: 42 },
  });

  // Create Array without compressor 
  await h.create_array('/deep/thought', {
    shape: 7500000,
    dtype: '>f2',
    chunk_shape: 42,
    compressor: null,
  });

  // Create a group 
  await h.create_group('/tricia/mcmillan', {
    attrs: { heart: 'gold', improbability: 'infinite' },
  });

  // View whole hierarchy
  const nodes = await h.get_nodes();
  console.log(nodes);
  //  Map(7) {
  //    '/arthur/dent' => 'array',
  //    '/arthur' => 'implicit_group',
  //    '/' => 'implicit_group',
  //    '/deep/thought' => 'array',
  //    '/deep' => 'implicit_group',
  //    '/tricia/mcmillan' => 'explicit_group',
  //    '/tricia' => 'implicit_group'
  //  }
})();

$ tree test.zr3
├── meta
│   └── root
│       ├── arthur
│       │   └── dent.array.json
│       ├── deep
│       │   └── thought.array.json
│       └── tricia
│           └── mcmillan.group.json
└── zarr.json

5 directories, 4 files

Development

$ npm install && npm test