fix infinite loop bug if no leaves

index.js

@@ -39,8 +39,7 @@ class MerkleTree {
   }
 
   createHashes(nodes) {
-
-    while (nodes.length !== 1) {
+    while (nodes.length > 1) {
 
       const layerIndex = this.layers.length
 
@@ -118,7 +117,7 @@ class MerkleTree {
    * const root = tree.getRoot()
    */
   getRoot() {
-    return this.layers[this.layers.length-1][0]
+    return this.layers[this.layers.length-1][0] || Buffer.from([])
   }
 
   /**

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "merkletreejs",
-  "version": "0.0.9",
+  "version": "0.0.14",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "merkletreejs",
-  "version": "0.0.14",
+  "version": "0.0.15",
   "description": "Construct Merkle Trees and verify proofs",
   "main": "index.js",
   "types": "index.d.ts",

test/index.js

@@ -222,3 +222,29 @@ test('sha-256 with option.isBitcoinTree', t => {
 
   t.equal(tree.verify(proof_0, leaves[0], root), true)
 })
+
+test('sha256 - no leaves', t => {
+  t.plan(1)
+
+  const leaves = []
+  const tree = new MerkleTree(leaves, sha256)
+
+  const root = ''
+  t.equal(tree.getRoot().toString('hex'), root)
+})
+
+test('sha256 - 1,000,000 leaves', t => {
+  t.plan(1)
+
+  let values = []
+  for (let i = 0; i < 1e6; i++) {
+    values.push(`${i}`)
+  }
+
+  const leaves = values.map(x => sha256(x))
+
+  const tree = new MerkleTree(leaves, sha256)
+
+  const root = '101dd357df60384d254330fe118e3046871767c2748ebd62ce031c117df483da'
+  t.equal(tree.getRoot().toString('hex'), root)
+})