Prepare package to self-host in Gitea npm registry

.npmrc

@@ -0,0 +1 @@
+@tornado:registry=https://git.tornado.ws/api/packages/tornado-packages/npm/

.nvmrc

@@ -0,0 +1 @@
+v14.21.3

package.json

@@ -1,9 +1,9 @@
 {
-  "name": "fixed-merkle-tree",
-  "version": "1.0.0",
+  "name": "@tornado/fixed-merkle-tree",
+  "version": "0.5.1",
   "description": "Fixed depth merkle tree implementation with sequential inserts",
-  "repository": "https://github.com/tornadocash/fixed-merkle-tree.git",
   "main": "src/merkleTree.js",
+  "repository": "https://git.tornado.ws/tornado-packages/fixed-merkle-tree.git",
   "scripts": {
     "test": "mocha",
     "lint": "eslint ."
@@ -18,6 +18,10 @@
   "files": [
     "src/*"
   ],
+  "dependencies": {
+    "@tornado/circomlib": "0.0.21",
+    "@tornado/snarkjs": "0.1.20"
+  },
   "devDependencies": {
     "babel-eslint": "^10.1.0",
     "chai": "^4.2.0",

src/merkleTree.js

@@ -1,5 +1,9 @@
-const defaultHash = require('./sha256')
+// keccak256("tornado") % BN254_FIELD_SIZE
+const DEFAULT_ZERO = '21663839004416932945382355908790599225266501822907911457504978515578255421292'
+const defaultHash = require('./mimc')
+
 // todo ensure consistent types in tree and inserted elements?
+// todo make sha3 default hasher (and update tests) to get rid of mimc/snarkjs/circomlib dependency
 
 /**
  * @callback hashFunction
@@ -18,21 +22,22 @@ class MerkleTree {
    * @param {hashFunction} [options.hashFunction] Function used to hash 2 leaves
    * @param [options.zeroElement] Value for non-existent leaves
    */
-  constructor(levels, elements = [], { hashFunction, zeroElement = 0 } = {}) {
+  constructor(levels, elements = [], { hashFunction, zeroElement = DEFAULT_ZERO } = {}) {
     this.levels = levels
     this.capacity = 2 ** levels
+    this.zeroElement = zeroElement
+    this._hash = hashFunction || defaultHash
     if (elements.length > this.capacity) {
       throw new Error('Tree is full')
     }
-    this._hash = hashFunction || defaultHash
-    this.zeroElement = zeroElement
+
     this._zeros = []
-    this._zeros[0] = zeroElement
+    this._layers = []
+    this._layers[0] = elements
+    this._zeros[0] = this.zeroElement
     for (let i = 1; i <= levels; i++) {
       this._zeros[i] = this._hash(this._zeros[i - 1], this._zeros[i - 1])
     }
-    this._layers = []
-    this._layers[0] = elements.slice()
     this._rebuild()
   }
 
@@ -70,30 +75,15 @@ class MerkleTree {
   }
 
   /**
-   * Insert multiple elements into the tree.
+   * Insert multiple elements into the tree. Tree will be fully rebuilt during this operation.
    * @param {Array} elements Elements to insert
    */
   bulkInsert(elements) {
     if (this._layers[0].length + elements.length > this.capacity) {
       throw new Error('Tree is full')
     }
-    // First we insert all elements except the last one
-    // updating only full subtree hashes (all layers where inserted element has odd index)
-    // the last element will update the full path to the root making the tree consistent again
-    for (let i = 0; i < elements.length - 1; i++) {
-      this._layers[0].push(elements[i])
-      let level = 0
-      let index = this._layers[0].length - 1
-      while (index % 2 === 1) {
-        level++
-        index >>= 1
-        this._layers[level][index] = this._hash(
-          this._layers[level - 1][index * 2],
-          this._layers[level - 1][index * 2 + 1],
-        )
-      }
-    }
-    this.insert(elements[elements.length - 1])
+    this._layers[0].push(...elements)
+    this._rebuild()
   }
 
   /**
@@ -162,14 +152,6 @@ class MerkleTree {
     return this._layers[0].slice()
   }
 
-  /**
-   * Returns a copy of n-th zero elements array
-   * @returns {Object[]}
-   */
-  zeros() {
-    return this._zeros.slice()
-  }
-
   /**
    * Serialize entire tree state including intermediate layers into a plain object
    * Deserializing it back will not require to recompute any hashes

src/mimc.js

@@ -0,0 +1,3 @@
+const { mimcsponge } = require('@tornado/circomlib')
+const { bigInt } = require('@tornado/snarkjs')
+module.exports = (left, right) => mimcsponge.multiHash([bigInt(left), bigInt(right)]).toString()

src/sha256.js

@@ -1,15 +0,0 @@
-const crypto = require('crypto')
-
-function toBuffer256(number) {
-  return Buffer.from(number.toString(16).padStart(512, '0'), 'hex')
-}
-
-function sha256(left, right) {
-  return crypto
-    .createHash('sha256')
-    .update(toBuffer256(left))
-    .update(toBuffer256(right))
-    .digest('hex')
-}
-
-module.exports = sha256

test/merkleTree.test.js

@@ -71,32 +71,6 @@ describe('MerkleTree', () => {
       tree.root().should.equal('10132905325673518287563057607527946096399700874345297651940963130460267058606')
     })
 
-    it('should give the same result as sequental inserts', () => {
-      const initialArray = [
-        [1],
-        [1, 2],
-        [1, 2, 3],
-        [1, 2, 3, 4],
-      ]
-      const insertedArray = [
-        [11],
-        [11, 12],
-        [11, 12, 13],
-        [11, 12, 13, 14],
-      ]
-      for (const initial of initialArray) {
-        for (const inserted of insertedArray) {
-          const tree1 = new MerkleTree(10, initial)
-          const tree2 = new MerkleTree(10, initial)
-          tree1.bulkInsert(inserted)
-          for (const item of inserted) {
-            tree2.insert(item)
-          }
-          tree1.root().should.equal(tree2.root())
-        }
-      }
-    }).timeout(10000)
-
     it('should work with max elements', () => {
       const tree = new MerkleTree(2, [1, 2])
       tree.bulkInsert([3, 4])