diff --git a/lib/build.js b/lib/build.js
index eea3278b..ac590436 100644
--- a/lib/build.js
+++ b/lib/build.js
@@ -1,55 +1,58 @@
-var fs = require('fs');
-var path = require('path');
-var conf = require('./config');
-var webpack = require('webpack');
-var merge = require('webpack-merge');
+var fs = require("fs");
+var path = require("path");
+var conf = require("./config");
+var webpack = require("webpack");
+var merge = require("webpack-merge");
 
 const testFilePattern = "\\.(test|spec)\\.?";
 
 // custom babel target for each node version
 function getBabelTarget(envConfig) {
-  var key = 'AWS_LAMBDA_JS_RUNTIME';
-  var runtimes = ['nodejs8.15.0', 'nodejs6.10.3'];
-  var current = envConfig[key] || process.env[key] || 'nodejs8.15.0';
+  var key = "AWS_LAMBDA_JS_RUNTIME";
+  var runtimes = ["nodejs8.15.0", "nodejs6.10.3"];
+  var current = envConfig[key] || process.env[key] || "nodejs8.15.0";
   var unknown = runtimes.indexOf(current) === -1;
-  return unknown ? '8.15.0' : current.replace(/^nodejs/, '');
+  return unknown ? "8.15.0" : current.replace(/^nodejs/, "");
 }
 
 function haveBabelrc(functionsDir) {
   const cwd = process.cwd();
 
   return (
-    fs.existsSync(path.join(cwd, '.babelrc')) ||
-    functionsDir.split('/').reduce((foundBabelrc, dir) => {
+    fs.existsSync(path.join(cwd, ".babelrc")) ||
+    functionsDir.split("/").reduce((foundBabelrc, dir) => {
       if (foundBabelrc) return foundBabelrc;
 
       const indexOf = functionsDir.indexOf(dir);
       const dirToSearch = functionsDir.substr(0, indexOf);
 
-      return fs.existsSync(path.join(cwd, dirToSearch, '.babelrc'));
+      return fs.existsSync(path.join(cwd, dirToSearch, ".babelrc"));
     }, false)
   );
 }
 
-function webpackConfig(dir, {userWebpackConfig, useBabelrc} = {}) {
+function webpackConfig(dir, { userWebpackConfig, useBabelrc } = {}) {
   var config = conf.load();
   var envConfig = conf.loadContext(config).environment;
   var babelOpts = { cacheDirectory: true };
   if (!haveBabelrc(dir)) {
     babelOpts.presets = [
-      [require.resolve('@babel/preset-env'), { targets: { node: getBabelTarget(envConfig) } }]
+      [
+        require.resolve("@babel/preset-env"),
+        { targets: { node: getBabelTarget(envConfig) } }
+      ]
     ];
 
     babelOpts.plugins = [
-      require.resolve('@babel/plugin-proposal-class-properties'),
-      require.resolve('@babel/plugin-transform-object-assign'),
-      require.resolve('@babel/plugin-proposal-object-rest-spread')
+      require.resolve("@babel/plugin-proposal-class-properties"),
+      require.resolve("@babel/plugin-transform-object-assign"),
+      require.resolve("@babel/plugin-proposal-object-rest-spread")
     ];
   }
 
   var functionsDir = config.build.functions || config.build.Functions;
-  var functionsPath = path.join(process.cwd(), functionsDir);
-  var dirPath = path.join(process.cwd(), dir);
+  var functionsPath = path.resolve(path.join(process.cwd(), functionsDir));
+  var dirPath = path.resolve(path.join(process.cwd(), dir));
 
   if (dirPath === functionsPath) {
     throw new Error(
@@ -66,20 +69,22 @@ function webpackConfig(dir, {userWebpackConfig, useBabelrc} = {}) {
   // Include environment variables from config if available
   var defineEnv = {};
   Object.keys(envConfig).forEach(key => {
-    defineEnv['process.env.' + key] = JSON.stringify(envConfig[key]);
+    defineEnv["process.env." + key] = JSON.stringify(envConfig[key]);
   });
 
   // Keep the same NODE_ENV if it was specified
-  var nodeEnv = process.env.NODE_ENV || 'production'
+  var nodeEnv = process.env.NODE_ENV || "production";
 
   // Set webpack mode based on the nodeEnv
-  var webpackMode = ['production', 'development'].includes(nodeEnv) ? nodeEnv : 'none'
+  var webpackMode = ["production", "development"].includes(nodeEnv)
+    ? nodeEnv
+    : "none";
 
   var webpackConfig = {
     mode: webpackMode,
     resolve: {
-      extensions: ['.wasm', '.mjs', '.js', '.json', '.ts'],
-      mainFields: ['module', 'main']
+      extensions: [".wasm", ".mjs", ".js", ".json", ".ts"],
+      mainFields: ["module", "main"]
     },
     module: {
       rules: [
@@ -89,23 +94,23 @@ function webpackConfig(dir, {userWebpackConfig, useBabelrc} = {}) {
             `(node_modules|bower_components|${testFilePattern})`
           ),
           use: {
-            loader: require.resolve('babel-loader'),
-            options: {...babelOpts, babelrc: useBabelrc}
+            loader: require.resolve("babel-loader"),
+            options: { ...babelOpts, babelrc: useBabelrc }
           }
         }
       ]
     },
     context: dirPath,
     entry: {},
-    target: 'node',
+    target: "node",
     plugins: [
       new webpack.IgnorePlugin(/vertx/),
       new webpack.DefinePlugin(defineEnv)
     ],
     output: {
       path: functionsPath,
-      filename: '[name].js',
-      libraryTarget: 'commonjs'
+      filename: "[name].js",
+      libraryTarget: "commonjs"
     },
     optimization: {
       nodeEnv
@@ -133,7 +138,10 @@ function webpackConfig(dir, {userWebpackConfig, useBabelrc} = {}) {
     );
   }
   if (userWebpackConfig) {
-    var webpackAdditional = require(path.join(process.cwd(), userWebpackConfig));
+    var webpackAdditional = require(path.join(
+      process.cwd(),
+      userWebpackConfig
+    ));
 
     return merge.smart(webpackConfig, webpackAdditional);
   }