From 107217f74d3952f9e7b070ac9716e3c1dcb790df Mon Sep 17 00:00:00 2001
From: Sergei SMART <sergei.smart@gmail.com>
Date: Tue, 22 Feb 2022 20:33:17 +1000
Subject: [PATCH] add getters

---
 src/index.ts            | 37 +++++++++++++++++++++++++++++++++--
 test/merkleTree.spec.ts | 43 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 78 insertions(+), 2 deletions(-)

diff --git a/src/index.ts b/src/index.ts
index 2c80a19..bdb7d15 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -6,6 +6,14 @@ const DEFAULT_ZERO = '2166383900441693294538235590879059922526650182290791145750
 const defaultHash = (left: Element, right: Element): string => mimcsponge.multiHash([BigInt(left), BigInt(right)]).toString()
 
 export default class MerkleTree {
+  get layers(): Array<Element[]> {
+    return this._layers.slice()
+  }
+
+  set layers(value: Array<Element[]>) {
+    this._layers = value
+  }
+
   levels: number
   capacity: number
   private _hash: HashFunction
@@ -186,17 +194,42 @@ export default class MerkleTree {
   /**
    * Returns a copy of non-zero tree elements.
    */
-  elements() {
+  get elements() {
     return this._layers[0].slice()
   }
 
   /**
    * Returns a copy of n-th zero elements array
    */
-  zeros() {
+  get zeros() {
     return this._zeros.slice()
   }
 
+  getLayersAsObject() {
+    const layers = this.layers
+    const objs = []
+    for (let i = 0; i < this.levels; i++) {
+      const arr = []
+      for (let j = 0; j < layers[i].length; j++) {
+        const obj = { [layers[i][j]]: null }
+        if (objs.length) {
+          obj[layers[i][j]] = {}
+          const a = objs.shift()
+          const akey = Object.keys(a)[0]
+          obj[layers[i][j]][akey] = a[akey]
+          if (objs.length) {
+            const b = objs.shift()
+            const bkey = Object.keys(b)[0]
+            obj[layers[i][j]][bkey] = b[bkey]
+          }
+        }
+        arr.push(obj)
+      }
+      objs.push(...arr)
+    }
+    return objs[0]
+  }
+
   /**
    * Serialize entire tree state including intermediate layers into a plain object
    * Deserializing it back will not require to recompute any hashes
diff --git a/test/merkleTree.spec.ts b/test/merkleTree.spec.ts
index 6690bee..5537540 100644
--- a/test/merkleTree.spec.ts
+++ b/test/merkleTree.spec.ts
@@ -1,5 +1,6 @@
 import MerkleTree from '../src'
 import { assert, should } from 'chai'
+import { it } from 'mocha'
 
 describe('MerkleTree', () => {
 
@@ -232,6 +233,48 @@ describe('MerkleTree', () => {
     })
   })
 
+  describe('#getters', () => {
+    const elements = [1, 2, 3, 4, 5]
+    const layers = [
+      [1, 2, 3, 4, 5],
+      [
+        '19814528709687996974327303300007262407299502847885145507292406548098437687919',
+        '9256022917525827637821171443533757190340579068025270193352322268529570863974',
+        '21652272025144185891702495507858700052653521882982711576347377471507927142323',
+      ],
+      [
+        '6464294476958346139385024074008223400825166653076969388043746597957512245037',
+        '21305827034995891902714687670641862055126514524916463201449278400604999416145',
+      ],
+      ['13482485030738390475684870940688026655293260583748749623167469686138055064771'],
+      ['5734482689596254215043546232260442114954448597263096309106433719494772338840'],
+    ]
+
+    it('should return same elements in array', () => {
+      const tree = new MerkleTree(10, elements)
+      assert.deepEqual(tree.elements, elements)
+    })
+    it('should return copy of elements array', () => {
+      const tree = new MerkleTree(10, elements)
+      const elements1 = tree.elements
+      tree.insert(6)
+      const elements2 = tree.elements
+      should().not.equal(elements1, elements2)
+    })
+
+    it('should return same layers in array', () => {
+      const tree = new MerkleTree(4, elements)
+      assert.deepEqual(tree.layers, layers)
+    })
+    it('should return copy of elements array', () => {
+      const tree = new MerkleTree(4, elements)
+      const layers1 = tree.layers
+      tree.insert(6)
+      const layers2 = tree.layers
+      should().not.equal(layers1, layers2)
+    })
+  })
+
   describe('#serialize', () => {
     it('should work', () => {
       const src = new MerkleTree(10, [1, 2, 3, 4, 5, 6, 7, 8, 9])