more test. fix nullish alloc

lib/PartialMerkleTree.js

@@ -76,6 +76,7 @@ class PartialMerkleTree extends BaseTree_1.BaseTree {
         this._processUpdate(index);
     }
     path(index) {
+        var _a;
         if (isNaN(Number(index)) || index < 0 || index >= this._layers[0].length) {
             throw new Error('Index out of bounds: ' + index);
         }
@@ -91,7 +92,7 @@ class PartialMerkleTree extends BaseTree_1.BaseTree {
             const leafIndex = elIndex ^ 1;
             if (leafIndex < this._layers[level].length) {
                 const [proofPos, proofEl] = this._proofMap.get(level);
-                pathElements[level] = this._layers[level][leafIndex] || (proofPos === leafIndex ? proofEl : null);
+                pathElements[level] = (_a = this._layers[level][leafIndex]) !== null && _a !== void 0 ? _a : (proofPos === leafIndex ? proofEl : null);
                 pathPositions[level] = leafIndex;
             }
             else {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "fixed-merkle-tree",
-  "version": "0.7.1",
+  "version": "0.7.2",
   "description": "Fixed depth merkle tree implementation with sequential inserts",
   "repository": "https://github.com/tornadocash/fixed-merkle-tree.git",
   "main": "lib/index.js",

src/PartialMerkleTree.ts

@@ -114,7 +114,7 @@ export class PartialMerkleTree extends BaseTree {
       const leafIndex = elIndex ^ 1
       if (leafIndex < this._layers[level].length) {
         const [proofPos, proofEl] = this._proofMap.get(level)
-        pathElements[level] = this._layers[level][leafIndex] || (proofPos === leafIndex ? proofEl : null)
+        pathElements[level] = this._layers[level][leafIndex] ?? (proofPos === leafIndex ? proofEl : null)
         pathPositions[level] = leafIndex
       } else {
         pathElements[level] = this._zeros[level]

test/fixedMerkleTree.spec.ts

@@ -294,7 +294,7 @@ describe('MerkleTree', () => {
   describe('#getTreeSlices', () => {
     let fullTree: MerkleTree
     before(async () => {
-      const elements = Array.from({ length: 2 ** 8 + 11 }, (_, i) => i)
+      const elements = Array.from({ length: 2 ** 10 }, (_, i) => i)
       fullTree = new MerkleTree(10, elements)
       return Promise.resolve()
     })
@@ -315,12 +315,21 @@ describe('MerkleTree', () => {
       const lastSlice = slices.pop()
       const partialTree = new PartialMerkleTree(10, lastSlice.edge, lastSlice.elements)
       slices.reverse().forEach(({ edge, elements }) => {
-        console.log(edge.edgeIndex, elements.length)
         partialTree.shiftEdge(edge, elements)
       })
       assert.deepEqual(fullTree.layers, partialTree.layers)
     }).timeout(10000)
 
+    it('should return same path', () => {
+      const slices = fullTree.getTreeSlices()
+      const lastSlice = slices.pop()
+      const partialTree = new PartialMerkleTree(10, lastSlice.edge, lastSlice.elements)
+      slices.reverse().forEach(({ edge, elements }) => {
+        partialTree.shiftEdge(edge, elements)
+      })
+      assert.deepEqual(fullTree.path(100), partialTree.path(100))
+    }).timeout(10000)
+
     it('should throw if invalid number of elements', () => {
       const [firstSlice] = fullTree.getTreeSlices()
       const call = () => new PartialMerkleTree(10, firstSlice.edge, firstSlice.elements)

test/partialMerkleTree.spec.ts

@@ -230,20 +230,30 @@ describe('PartialMerkleTree', () => {
     })
   })
   describe('#shiftEdge', () => {
+    const levels = 20
+    const elements: Element[] = Array.from({ length: 2 ** 18 }, (_, i) => i)
+    const tree = new MerkleTree(levels, elements)
     it('should work', () => {
-      const levels = 10
-      const elements: Element[] = Array.from({ length: 21 ** 2 }, (_, i) => i)
-      const tree = new MerkleTree(levels, elements)
       const edge1 = tree.getTreeEdge(200)
       const edge2 = tree.getTreeEdge(100)
-      const edge3 = tree.getTreeEdge(10)
       const partialTree = new PartialMerkleTree(levels, edge1, elements.slice(edge1.edgeIndex))
       partialTree.shiftEdge(edge2, elements.slice(edge2.edgeIndex, partialTree.edgeIndex))
-      partialTree.shiftEdge(edge3, elements.slice(edge3.edgeIndex, partialTree.edgeIndex))
       tree.insert('1111')
       partialTree.insert('1111')
-      assert.deepEqual(partialTree.path(50), tree.path(50))
+      assert.deepEqual(partialTree.path(150), tree.path(150))
     })
+    it('should be able to build full tree from slices', () => {
+      const slices = tree.getTreeSlices(6)
+      const lastSlice = slices.pop()
+      const partialTree = new PartialMerkleTree(levels, lastSlice.edge, lastSlice.elements)
+      for (let i = slices.length - 1; i >= 0; i--) {
+        partialTree.shiftEdge(slices[i].edge, slices[i].elements)
+      }
+      partialTree.insert('1')
+      tree.insert('1')
+      assert.deepStrictEqual(partialTree.path(432), tree.path(432))
+    }).timeout(10000)
+
     it('should fail if new edge index is over current edge', () => {
       const { fullTree, partialTree } = getTestTrees(10, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9], 4)
       const newEdge = fullTree.getTreeEdge(4)