This is a fork from Herodotus Dev Ltd's merkle-mountain-ranges npm package altered to fit Nostr protocol ecosystem

Installing the package

$> npm i nmmr

Usage

import nmmr from 'nmmr'

// Append data as bytes then save chunks to nostr event
const t = new TextEncoder()
const nmmr = new NMMR()
await nmmr.append(t.encode('a'))
await nmmr.append(t.encode('b'))
for await (const chunk of nmmr.getChunks()) {
  // You should code this part yourself
  await createAndPublishNostrEvent(chunk)
}

// Later verify some chunk is really part of the whole
NMMR.verifyProof(chunk)

Manually Using the Merkle Mountaing Range

Note: Prefer using the above default export.

import { InMemoryMMR } from 'nmmr'

const mmr = new InMemoryMMR()
const leaves = 11 // Total node size will be 19
for (let idx = 0; idx < leaves; ++idx) {
  await mmr.append((idx + 1).toString()) // Leaf number starts at 1 in this implementation.
}
/*
   Height
      3              15
                  /     \
                 /       \
                /         \
               /           \
      2       7            14
            /    \       /    \
      1    3     6     10     13     18
          / \   / \    / \   /  \   /  \
      0  1   2 4   5  8   9 11  12 16  17 19
*/

// Generating a proof for leaf no.9 (16th node in the inclusion diagram above)
const proof = mmr.getProof(9)
console.log('Inclusion proof of leaf no.9', proof)
// Verifying the proof (throws on failure, pass on success)
mmr.verifyProof(proof)
console.log('Valid proof!')
// Inclusion proof of leaf no.9 {
//   index: 9,
//   value: '6',
//   peaks: [ 15, 18, 19 ],
//   peaksHashes: [
//     '0x7811cf3bd6a5f019f9c345900f760694309d019be0766007388665145c431b3',
//     '0x5ad94a9ad7f469929d8e513ddb87e8758bddc928b06dede8c9e248630ed48f9',
//     '0x197f42d06f2cf19f82d475673f16350416f2c9180d77bea8a3bcc29d27b7325'
//   ],
//   siblingHashes: [
//     '0x3531a94afdc03b1ee109786fdddaf23a7864c8f18ddff9d552b5dfb50ac66a',
//     '0x41132c938a98be60612de7aed9daa905f91c8390f731c7fde8fb8bd59bbe4c3',
//     '0x4a1fead9ecdd90793ba10b7da6e8a30d655843296f148f147a89cb3e978528'
//   ],
//   lastVisitedNodeIdx: 15
// }
// Valid proof!

License

GNU GPLv3