diff --git a/lib/MerkleTree.js b/lib/MerkleTree.js
index e5f952e..f0e6ffa 100644
--- a/lib/MerkleTree.js
+++ b/lib/MerkleTree.js
@@ -1,99 +1,99 @@
-const jsStorage = require("./Storage");
-const mimcHasher = require("./MiMC");
+const jsStorage = require('./Storage')
+const mimcHasher = require('./MiMC')
 
 class MerkleTree {
 
   constructor(n_levels, zero_value, defaultElements, prefix, storage, hasher) {
-    this.prefix = prefix;
-    this.storage = storage || new jsStorage();
-    this.hasher = hasher || new mimcHasher();
-    this.n_levels = n_levels;
-    this.zero_values = [];
-    this.totalElements = 0;
+    this.prefix = prefix
+    this.storage = storage || new jsStorage()
+    this.hasher = hasher || new mimcHasher()
+    this.n_levels = n_levels
+    this.zero_values = []
+    this.totalElements = 0
 
-    let current_zero_value = zero_value || 0;
-    this.zero_values.push(current_zero_value);
+    let current_zero_value = zero_value || 0
+    this.zero_values.push(current_zero_value)
     for (let i = 0; i < n_levels; i++) {
-      current_zero_value = this.hasher.hash(i, current_zero_value, current_zero_value);
+      current_zero_value = this.hasher.hash(i, current_zero_value, current_zero_value)
       this.zero_values.push(
         current_zero_value.toString(),
-      );
+      )
     }
     if (defaultElements) {
-        let level = 0
-        this.totalElements = defaultElements.length
-        defaultElements.forEach((element, i) => {
-            this.storage.put(MerkleTree.index_to_key(prefix, level, i), element)
-        })
-        level++
-        let numberOfElementInRow = Math.ceil(defaultElements.length / 2)
-        for (level; level <= this.n_levels; level++) {
-            for(let i = 0; i < numberOfElementInRow; i++) {
-                const leftKey = MerkleTree.index_to_key(prefix, level - 1, 2 * i)
-                const rightKey = MerkleTree.index_to_key(prefix, level - 1, 2 * i + 1)
+      let level = 0
+      this.totalElements = defaultElements.length
+      defaultElements.forEach((element, i) => {
+        this.storage.put(MerkleTree.index_to_key(prefix, level, i), element)
+      })
+      level++
+      let numberOfElementInRow = Math.ceil(defaultElements.length / 2)
+      for (level; level <= this.n_levels; level++) {
+        for(let i = 0; i < numberOfElementInRow; i++) {
+          const leftKey = MerkleTree.index_to_key(prefix, level - 1, 2 * i)
+          const rightKey = MerkleTree.index_to_key(prefix, level - 1, 2 * i + 1)
 
-                const left = this.storage.get(leftKey)
-                const right = this.storage.get_or_element(rightKey, this.zero_values[level - 1])
+          const left = this.storage.get(leftKey)
+          const right = this.storage.get_or_element(rightKey, this.zero_values[level - 1])
 
-                const subRoot = this.hasher.hash(null, left, right);
-                this.storage.put(MerkleTree.index_to_key(prefix, level, i), subRoot)
-            }
-            numberOfElementInRow = Math.max(Math.ceil(numberOfElementInRow / 2), 1)
+          const subRoot = this.hasher.hash(null, left, right)
+          this.storage.put(MerkleTree.index_to_key(prefix, level, i), subRoot)
         }
+        numberOfElementInRow = Math.max(Math.ceil(numberOfElementInRow / 2), 1)
+      }
     }
   }
 
   static index_to_key(prefix, level, index) {
-    const key = `${prefix}_tree_${level}_${index}`;
-    return key;
+    const key = `${prefix}_tree_${level}_${index}`
+    return key
   }
 
   async root() {
     let root = await this.storage.get_or_element(
       MerkleTree.index_to_key(this.prefix, this.n_levels, 0),
       this.zero_values[this.n_levels],
-    );
+    )
 
-    return root;
+    return root
   }
 
   async path(index) {
     class PathTraverser {
       constructor(prefix, storage, zero_values) {
-        this.prefix = prefix;
-        this.storage = storage;
-        this.zero_values = zero_values;
-        this.path_elements = [];
-        this.path_index = [];
+        this.prefix = prefix
+        this.storage = storage
+        this.zero_values = zero_values
+        this.path_elements = []
+        this.path_index = []
       }
 
       async handle_index(level, element_index, sibling_index) {
         const sibling = await this.storage.get_or_element(
           MerkleTree.index_to_key(this.prefix, level, sibling_index),
           this.zero_values[level],
-        );
-        this.path_elements.push(sibling);
-        this.path_index.push(element_index % 2);
+        )
+        this.path_elements.push(sibling)
+        this.path_index.push(element_index % 2)
       }
     }
-    let traverser = new PathTraverser(this.prefix, this.storage, this.zero_values);
+    let traverser = new PathTraverser(this.prefix, this.storage, this.zero_values)
     const root = await this.storage.get_or_element(
       MerkleTree.index_to_key(this.prefix, this.n_levels, 0),
       this.zero_values[this.n_levels],
-    );
+    )
 
     const element = await this.storage.get_or_element(
       MerkleTree.index_to_key(this.prefix, 0, index),
       this.zero_values[0],
-    );
+    )
 
-    await this.traverse(index, traverser);
+    await this.traverse(index, traverser)
     return {
       root,
       path_elements: traverser.path_elements,
       path_index: traverser.path_index,
       element
-    };
+    }
   }
 
   async update(index, element, insert = false) {
@@ -105,12 +105,12 @@ class MerkleTree {
     try {
       class UpdateTraverser {
         constructor(prefix, storage, hasher, element, zero_values) {
-          this.prefix = prefix;
-          this.current_element = element;
-          this.zero_values = zero_values;
-          this.storage = storage;
-          this.hasher = hasher;
-          this.key_values_to_put = [];
+          this.prefix = prefix
+          this.current_element = element
+          this.zero_values = zero_values
+          this.storage = storage
+          this.hasher = hasher
+          this.key_values_to_put = []
         }
 
         async handle_index(level, element_index, sibling_index) {
@@ -118,26 +118,26 @@ class MerkleTree {
             this.original_element = await this.storage.get_or_element(
               MerkleTree.index_to_key(this.prefix, level, element_index),
               this.zero_values[level],
-            );
+            )
           }
           const sibling = await this.storage.get_or_element(
             MerkleTree.index_to_key(this.prefix, level, sibling_index),
             this.zero_values[level],
-          );
-          let left, right;
+          )
+          let left, right
           if (element_index % 2 == 0) {
-            left = this.current_element;
-            right = sibling;
+            left = this.current_element
+            right = sibling
           } else {
-            left = sibling;
-            right = this.current_element;
+            left = sibling
+            right = this.current_element
           }
 
           this.key_values_to_put.push({
             key: MerkleTree.index_to_key(this.prefix, level, element_index),
             value: this.current_element,
-          });
-          this.current_element = this.hasher.hash(level, left, right);
+          })
+          this.current_element = this.hasher.hash(level, left, right)
         }
       }
       let traverser = new UpdateTraverser(
@@ -146,17 +146,17 @@ class MerkleTree {
         this.hasher,
         element,
         this.zero_values
-      );
+      )
 
-      await this.traverse(index, traverser);
+      await this.traverse(index, traverser)
       traverser.key_values_to_put.push({
         key: MerkleTree.index_to_key(this.prefix, this.n_levels, 0),
         value: traverser.current_element,
-      });
+      })
 
-      await this.storage.put_batch(traverser.key_values_to_put);
+      await this.storage.put_batch(traverser.key_values_to_put)
     } catch(e) {
-        console.error(e)
+      console.error(e)
     }
   }
 
@@ -167,18 +167,18 @@ class MerkleTree {
   }
 
   async traverse(index, handler) {
-    let current_index = index;
+    let current_index = index
     for (let i = 0; i < this.n_levels; i++) {
-        let sibling_index = current_index;
-        if (current_index % 2 == 0) {
-          sibling_index += 1;
-        } else {
-          sibling_index -= 1;
-        }
-        await handler.handle_index(i, current_index, sibling_index);
-        current_index = Math.floor(current_index / 2);
+      let sibling_index = current_index
+      if (current_index % 2 == 0) {
+        sibling_index += 1
+      } else {
+        sibling_index -= 1
       }
+      await handler.handle_index(i, current_index, sibling_index)
+      current_index = Math.floor(current_index / 2)
+    }
   }
 }
 
-module.exports = MerkleTree;
+module.exports = MerkleTree
diff --git a/lib/MiMC.js b/lib/MiMC.js
index 843ec91..d070373 100644
--- a/lib/MiMC.js
+++ b/lib/MiMC.js
@@ -1,13 +1,13 @@
-const circomlib = require('circomlib');
-const mimcsponge = circomlib.mimcsponge;
-const snarkjs = require('snarkjs');
+const circomlib = require('circomlib')
+const mimcsponge = circomlib.mimcsponge
+const snarkjs = require('snarkjs')
 
-const bigInt = snarkjs.bigInt;
+const bigInt = snarkjs.bigInt
 
 class MimcSpongeHasher {
-    hash(level, left, right) {
-        return mimcsponge.multiHash([bigInt(left), bigInt(right)]).toString();
-    }
+  hash(level, left, right) {
+    return mimcsponge.multiHash([bigInt(left), bigInt(right)]).toString()
+  }
 }
 
-module.exports = MimcSpongeHasher;
\ No newline at end of file
+module.exports = MimcSpongeHasher
diff --git a/lib/Storage.js b/lib/Storage.js
index ae86fc0..52b97d6 100644
--- a/lib/Storage.js
+++ b/lib/Storage.js
@@ -2,38 +2,38 @@
 
 class JsStorage {
   constructor() {
-    this.db = {};
+    this.db = {}
   }
 
   get(key) {
-    return this.db[key];
+    return this.db[key]
   }
 
   get_or_element(key, defaultElement) {
-    const element = this.db[key];
+    const element = this.db[key]
     if (element === undefined) {
-        return defaultElement;
+      return defaultElement
     } else {
-        return element
+      return element
     }
   }
 
   put(key, value) {
     if (key === undefined || value === undefined) {
-        throw Error('key or value is undefined')
+      throw Error('key or value is undefined')
     }
-    this.db[key] = value;
+    this.db[key] = value
   }
 
   del(key) {
-    delete this.db[key];
+    delete this.db[key]
   }
 
   put_batch(key_values) {
     key_values.forEach(element => {
-        this.db[element.key] = element.value;
-    });
+      this.db[element.key] = element.value
+    })
   }
 }
 
-module.exports = JsStorage;
\ No newline at end of file
+module.exports = JsStorage
diff --git a/migrations/1_initial_migration.js b/migrations/1_initial_migration.js
index ee2135d..a7a4fdb 100644
--- a/migrations/1_initial_migration.js
+++ b/migrations/1_initial_migration.js
@@ -1,5 +1,5 @@
-const Migrations = artifacts.require("Migrations");
+const Migrations = artifacts.require('Migrations')
 
 module.exports = function(deployer) {
-  deployer.deploy(Migrations);
-};
+  deployer.deploy(Migrations)
+}
diff --git a/migrations/2_deploy_mimc.js b/migrations/2_deploy_mimc.js
index a920eab..a299f10 100644
--- a/migrations/2_deploy_mimc.js
+++ b/migrations/2_deploy_mimc.js
@@ -1,24 +1,23 @@
-const path = require('path');
+const path = require('path')
 
-const mimcGenContract = require('circomlib/src/mimcsponge_gencontract.js');
-const Artifactor = require('truffle-artifactor');
+const mimcGenContract = require('circomlib/src/mimcsponge_gencontract.js')
+const Artifactor = require('truffle-artifactor')
 
-const SEED = 'mimcsponge';
+const SEED = 'mimcsponge'
 
 
 module.exports = function(deployer) {
   return deployer.then( async () =>  {
-    const contractsDir = path.join(__dirname, '..', 'build/contracts');
-    let artifactor = new Artifactor(contractsDir);
-    let mimcContractName = 'MiMC';
+    const contractsDir = path.join(__dirname, '..', 'build/contracts')
+    let artifactor = new Artifactor(contractsDir)
+    let mimcContractName = 'MiMC'
     await artifactor.save({
       contractName: mimcContractName,
       abi: mimcGenContract.abi,
       unlinked_binary: mimcGenContract.createCode(SEED, 220),
+    }).then(async () => {
+      const MiMC = artifacts.require(mimcContractName)
+      await deployer.deploy(MiMC)
     })
-    .then(async () => {
-      const MiMC = artifacts.require(mimcContractName);
-      await deployer.deploy(MiMC);
-    });
-  });
-};
+  })
+}
diff --git a/migrations/3_deploy_verifier.js b/migrations/3_deploy_verifier.js
index 235901b..edd1a94 100644
--- a/migrations/3_deploy_verifier.js
+++ b/migrations/3_deploy_verifier.js
@@ -1,6 +1,6 @@
 require('dotenv').config()
-const Verifier = artifacts.require("Verifier");
+const Verifier = artifacts.require('Verifier')
 
 module.exports = function(deployer) {
-  deployer.deploy(Verifier);
-};
+  deployer.deploy(Verifier)
+}
diff --git a/migrations/4_deploy_mixer.js b/migrations/4_deploy_mixer.js
index 675ba91..b605fb6 100644
--- a/migrations/4_deploy_mixer.js
+++ b/migrations/4_deploy_mixer.js
@@ -1,7 +1,7 @@
 require('dotenv').config({ path: '../.env' })
-const Mixer = artifacts.require("Mixer");
-const Verifier = artifacts.require("Verifier");
-const MiMC = artifacts.require("MiMC");
+const Mixer = artifacts.require('Mixer')
+const Verifier = artifacts.require('Verifier')
+const MiMC = artifacts.require('MiMC')
 
 
 module.exports = function(deployer) {
@@ -11,6 +11,6 @@ module.exports = function(deployer) {
     const miMC = await MiMC.deployed()
     await Mixer.link(MiMC, miMC.address)
     const mixer = await deployer.deploy(Mixer, verifier.address, AMOUNT, MERKLE_TREE_HEIGHT, EMPTY_ELEMENT)
-    console.log("Mixer's address ", mixer.address)
+    console.log('Mixer\'s address ', mixer.address)
   })
-};
+}
diff --git a/truffle-config.js b/truffle-config.js
index 369ada4..56a0b2a 100644
--- a/truffle-config.js
+++ b/truffle-config.js
@@ -1,5 +1,5 @@
 require('dotenv').config()
-const HDWalletProvider = require('truffle-hdwallet-provider');
+const HDWalletProvider = require('truffle-hdwallet-provider')
 const utils = require('web3-utils')
 // const infuraKey = "fj4jll3k.....";
 //
@@ -25,19 +25,19 @@ module.exports = {
     // options below to some value.
 
     development: {
-     host: "127.0.0.1",     // Localhost (default: none)
-     port: 8545,            // Standard Ethereum port (default: none)
-     network_id: "*",       // Any network (default: none)
+      host: '127.0.0.1',     // Localhost (default: none)
+      port: 8545,            // Standard Ethereum port (default: none)
+      network_id: '*',       // Any network (default: none)
     },
 
     // Another network with more advanced options...
     // advanced: {
-      // port: 8777,             // Custom port
-      // network_id: 1342,       // Custom network
-      // gas: 8500000,           // Gas sent with each transaction (default: ~6700000)
-      // gasPrice: 20000000000,  // 20 gwei (in wei) (default: 100 gwei)
-      // from: <address>,        // Account to send txs from (default: accounts[0])
-      // websockets: true        // Enable EventEmitter interface for web3 (default: false)
+    //   port: 8777,             // Custom port
+    //   network_id: 1342,       // Custom network
+    //   gas: 8500000,           // Gas sent with each transaction (default: ~6700000)
+    //   gasPrice: 20000000000,  // 20 gwei (in wei) (default: 100 gwei)
+    //   from: <address>,        // Account to send txs from (default: accounts[0])
+    //   websockets: true        // Enable EventEmitter interface for web3 (default: false)
     // },
 
     // Useful for deploying to a public network.
@@ -54,9 +54,9 @@ module.exports = {
 
     // Useful for private networks
     // private: {
-      // provider: () => new HDWalletProvider(mnemonic, `https://network.io`),
-      // network_id: 2111,   // This network is yours, in the cloud.
-      // production: true    // Treats this network as if it was a public net. (default: false)
+    //   provider: () => new HDWalletProvider(mnemonic, `https://network.io`),
+    //   network_id: 2111,   // This network is yours, in the cloud.
+    //   production: true    // Treats this network as if it was a public net. (default: false)
     // }
   },
 
@@ -68,14 +68,14 @@ module.exports = {
   // Configure your compilers
   compilers: {
     solc: {
-      version: "0.5.8",    // Fetch exact version from solc-bin (default: truffle's version)
+      version: '0.5.8',    // Fetch exact version from solc-bin (default: truffle's version)
       // docker: true,        // Use "0.5.1" you've installed locally with docker (default: false)
       settings: {          // See the solidity docs for advice about optimization and evmVersion
-       optimizer: {
-         enabled: false,
-         runs: 200
-       },
-       // evmVersion: "byzantium"
+        optimizer: {
+          enabled: false,
+          runs: 200
+        },
+        // evmVersion: "byzantium"
       }
     }
   }