201-storage.js

/* eslint-disable no-console */

import { unixfs } from '@helia/unixfs'
import { MemoryBlockstore } from 'blockstore-core'
import { createHelia } from 'helia'

// the blockstore is where we store the blocks that make up files. this blockstore
// stores everything in-memory - other blockstores are available:
//   - https://www.npmjs.com/package/blockstore-fs - a filesystem blockstore (for use in node)
//   - https://www.npmjs.com/package/blockstore-idb - an IndexDB blockstore (for use in browsers)
//   - https://www.npmjs.com/package/blockstore-level - a LevelDB blockstore (for node or browsers,
//                                        though storing files in a database is rarely a good idea)
const blockstore = new MemoryBlockstore()

// create a Helia node
const helia = await createHelia({
  blockstore
})

// create a filesystem on top of Helia, in this case it's UnixFS
const fs = unixfs(helia)

// we will use this TextEncoder to turn strings into Uint8Arrays
const encoder = new TextEncoder()

// add the bytes to your node and receive a unique content identifier
const cid = await fs.addBytes(encoder.encode('Hello World 201'))

console.log('Added file:', cid.toString())

// create a second Helia node using the same blockstore
const helia2 = await createHelia({
  blockstore
})

// create a second filesystem
const fs2 = unixfs(helia2)

// this decoder will turn Uint8Arrays into strings
const decoder = new TextDecoder()
let text = ''

// read the file from the blockstore using the second Helia node
for await (const chunk of fs2.cat(cid)) {
  text += decoder.decode(chunk, {
    stream: true
  })
}

console.log('Added file contents:', text)