diff --git a/.npmignore b/.npmignore
deleted file mode 100644
index a6d89df..0000000
--- a/.npmignore
+++ /dev/null
@@ -1,4 +0,0 @@
-.github
-.eslintrc
-.editorconfig
-test
diff --git a/package.json b/package.json
index 097e51e..4ac27f4 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "fixed-merkle-tree",
-  "version": "0.1.0",
+  "version": "0.2.0",
   "description": "Fixed depth merkle tree implementation with sequential inserts",
   "main": "src/merkleTree.js",
   "scripts": {
@@ -10,6 +10,7 @@
   "keywords": ["merkle", "tree", "merkleTree"],
   "author": "Roman Semenov <semenov.roma@gmail.com>",
   "license": "ISC",
+  "files": ["src/*"],
   "dependencies": {
     "snarkjs": "git+https://github.com/tornadocash/snarkjs.git#869181cfaf7526fe8972073d31655493a04326d5",
     "circomlib": "git+https://github.com/tornadocash/circomlib.git#c372f14d324d57339c88451834bf2824e73bbdbc"
diff --git a/src/merkleTree.js b/src/merkleTree.js
index e37a7f7..9aaf508 100644
--- a/src/merkleTree.js
+++ b/src/merkleTree.js
@@ -18,10 +18,11 @@ class MerkleTree {
    * Constructor
    * @param {number} levels Number of levels in the tree
    * @param {Array} [elements] Initial elements
-   * @param [zeroElement] Value for non-existent leaves
-   * @param {hashFunction} [hashFunction] Function used to hash 2 leaves
+   * @param {Object} options
+   * @param {hashFunction} [options.hashFunction] Function used to hash 2 leaves
+   * @param [options.zeroElement] Value for non-existent leaves
    */
-  constructor(levels, elements = [], zeroElement = DEFAULT_ZERO, hashFunction) {
+  constructor(levels, elements = [], { hashFunction, zeroElement = DEFAULT_ZERO } = {}) {
     this.levels = levels
     this.capacity = 2 << levels
     this.zeroElement = zeroElement
@@ -113,9 +114,9 @@ class MerkleTree {
       throw new Error('Index out of bounds: ' + index)
     }
     const pathElements = []
-    const pathIndex = []
+    const pathIndices = []
     for (let level = 0; level < this.levels; level++) {
-      pathIndex[level] = index % 2
+      pathIndices[level] = index % 2
       pathElements[level] = (index ^ 1) < this._layers[level].length ?
         this._layers[level][index ^ 1] :
         this._zeros[level]
@@ -123,7 +124,7 @@ class MerkleTree {
     }
     return {
       pathElements,
-      pathIndex,
+      pathIndices,
     }
   }
 
@@ -135,6 +136,14 @@ class MerkleTree {
   indexOf(element) {
     return this._layers[0].indexOf(element)
   }
+
+  /**
+   * Returns a copy of non-zero tree elements
+   * @returns {Object[]}
+   */
+  elements() {
+    return this._layers[0].slice()
+  }
 }
 
 module.exports = MerkleTree
diff --git a/test/merkleTree.test.js b/test/merkleTree.test.js
index e2e54d1..63ec932 100644
--- a/test/merkleTree.test.js
+++ b/test/merkleTree.test.js
@@ -89,7 +89,7 @@ describe('MerkleTree', () => {
     it('should work for even index', () => {
       const tree = new MerkleTree(10, [1, 2, 3, 4, 5])
       const proof = tree.proof(2)
-      proof.pathIndex.should.be.deep.equal([0, 1, 0, 0, 0, 0, 0, 0, 0, 0])
+      proof.pathIndices.should.be.deep.equal([0, 1, 0, 0, 0, 0, 0, 0, 0, 0])
       proof.pathElements.should.be.deep.equal([
         4,
         '19814528709687996974327303300007262407299502847885145507292406548098437687919',
@@ -107,7 +107,7 @@ describe('MerkleTree', () => {
     it('should work for odd index', () => {
       const tree = new MerkleTree(10, [1, 2, 3, 4, 5])
       const proof = tree.proof(3)
-      proof.pathIndex.should.be.deep.equal([1, 1, 0, 0, 0, 0, 0, 0, 0, 0])
+      proof.pathIndices.should.be.deep.equal([1, 1, 0, 0, 0, 0, 0, 0, 0, 0])
       proof.pathElements.should.be.deep.equal([
         3,
         '19814528709687996974327303300007262407299502847885145507292406548098437687919',