diff --git a/lib/modules/perf/index.js b/lib/modules/perf/index.js
index 48f8c619..3d25ecfb 100644
--- a/lib/modules/perf/index.js
+++ b/lib/modules/perf/index.js
@@ -6,6 +6,8 @@ export default class PerformanceMonitoring extends ModuleBase {
   static _NAMESPACE = 'perf';
   static _NATIVE_MODULE = 'RNFirebasePerformance';
 
+  _native: Object;
+
   constructor(firebaseApp: Object, options: Object = {}) {
     super(firebaseApp, options);
   }
@@ -26,8 +28,4 @@ export default class PerformanceMonitoring extends ModuleBase {
   newTrace(trace: string): void {
     return new Trace(this, trace);
   }
-
-  get namespace(): string {
-    return 'firebase:perf';
-  }
 }
diff --git a/lib/utils/index.js b/lib/utils/index.js
index 716cea30..4652ef73 100644
--- a/lib/utils/index.js
+++ b/lib/utils/index.js
@@ -6,7 +6,8 @@ import { Platform } from 'react-native';
 // modeled after base64 web-safe chars, but ordered by ASCII
 const PUSH_CHARS = '-0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz';
 const hasOwnProperty = Object.hasOwnProperty;
-const DEFAULT_CHUNK_SIZE = 50;
+
+// const DEFAULT_CHUNK_SIZE = 50;
 
 /**
  * Deep get a value from an object.
@@ -129,63 +130,63 @@ export function noop(): void {
 }
 
 
-/**
- * Delays chunks based on sizes per event loop.
- * @param collection
- * @param chunkSize
- * @param operation
- * @param callback
- * @private
- */
-function _delayChunk(collection: Array<*>,
-                     chunkSize: number,
-                     operation: Function,
-                     callback: Function): void {
-  const length = collection.length;
-  const iterations = Math.ceil(length / chunkSize);
-
-  // noinspection ES6ConvertVarToLetConst
-  let thisIteration = 0;
-
-  setImmediate(function next() {
-    const start = thisIteration * chunkSize;
-    const _end = start + chunkSize;
-    const end = _end >= length ? length : _end;
-    const result = operation(collection.slice(start, end), start, end);
-
-    if (thisIteration++ > iterations) {
-      callback(null, result);
-    } else {
-      setImmediate(next);
-    }
-  });
-}
-
-/**
- * Async each with optional chunk size limit
- * @param array
- * @param chunkSize
- * @param iterator
- * @param cb
- */
-export function each(array: Array<*>,
-                     chunkSize: number | Function,
-                     iterator: Function,
-                     cb?: Function): void {
-  if (typeof chunkSize === 'function') {
-    cb = iterator;
-    iterator = chunkSize;
-    chunkSize = DEFAULT_CHUNK_SIZE;
-  }
-
-  if (cb) {
-    _delayChunk(array, chunkSize, (slice, start) => {
-      for (let ii = 0, jj = slice.length; ii < jj; ii += 1) {
-        iterator(slice[ii], start + ii);
-      }
-    }, cb);
-  }
-}
+// /**
+//  * Delays chunks based on sizes per event loop.
+//  * @param collection
+//  * @param chunkSize
+//  * @param operation
+//  * @param callback
+//  * @private
+//  */
+// function _delayChunk(collection: Array<*>,
+//                      chunkSize: number,
+//                      operation: Function,
+//                      callback: Function): void {
+//   const length = collection.length;
+//   const iterations = Math.ceil(length / chunkSize);
+//
+//   // noinspection ES6ConvertVarToLetConst
+//   let thisIteration = 0;
+//
+//   setImmediate(function next() {
+//     const start = thisIteration * chunkSize;
+//     const _end = start + chunkSize;
+//     const end = _end >= length ? length : _end;
+//     const result = operation(collection.slice(start, end), start, end);
+//
+//     if (thisIteration++ > iterations) {
+//       callback(null, result);
+//     } else {
+//       setImmediate(next);
+//     }
+//   });
+// }
+//
+// /**
+//  * Async each with optional chunk size limit
+//  * @param array
+//  * @param chunkSize
+//  * @param iterator
+//  * @param cb
+//  */
+// export function each(array: Array<*>,
+//                      chunkSize: number | Function,
+//                      iterator: Function,
+//                      cb?: Function): void {
+//   if (typeof chunkSize === 'function') {
+//     cb = iterator;
+//     iterator = chunkSize;
+//     chunkSize = DEFAULT_CHUNK_SIZE;
+//   }
+//
+//   if (cb) {
+//     _delayChunk(array, chunkSize, (slice, start) => {
+//       for (let ii = 0, jj = slice.length; ii < jj; ii += 1) {
+//         iterator(slice[ii], start + ii);
+//       }
+//     }, cb);
+//   }
+// }
 
 /**
  * Returns a string typeof that's valid for Firebase usage
@@ -198,41 +199,41 @@ export function typeOf(value: any): string {
   return typeof value;
 }
 
-/**
- * Async map with optional chunk size limit
- * @param array
- * @param chunkSize
- * @param iterator
- * @param cb
- * @returns {*}
- */
-export function map(array: Array<*>,
-                    chunkSize: number | Function,
-                    iterator: Function,
-                    cb?: Function): void {
-  if (typeof chunkSize === 'function') {
-    cb = iterator;
-    iterator = chunkSize;
-    chunkSize = DEFAULT_CHUNK_SIZE;
-  }
+// /**
+//  * Async map with optional chunk size limit
+//  * @param array
+//  * @param chunkSize
+//  * @param iterator
+//  * @param cb
+//  * @returns {*}
+//  */
+// export function map(array: Array<*>,
+//                     chunkSize: number | Function,
+//                     iterator: Function,
+//                     cb?: Function): void {
+//   if (typeof chunkSize === 'function') {
+//     cb = iterator;
+//     iterator = chunkSize;
+//     chunkSize = DEFAULT_CHUNK_SIZE;
+//   }
+//
+//   const result = [];
+//   _delayChunk(array, chunkSize, (slice, start) => {
+//     for (let ii = 0, jj = slice.length; ii < jj; ii += 1) {
+//       result.push(iterator(slice[ii], start + ii, array));
+//     }
+//     return result;
+//   }, () => cb && cb(result));
+// }
 
-  const result = [];
-  _delayChunk(array, chunkSize, (slice, start) => {
-    for (let ii = 0, jj = slice.length; ii < jj; ii += 1) {
-      result.push(iterator(slice[ii], start + ii, array));
-    }
-    return result;
-  }, () => cb && cb(result));
-}
-
-/**
- *
- * @param string
- * @return {string}
- */
-export function capitalizeFirstLetter(string: String) {
-  return `${string.charAt(0).toUpperCase()}${string.slice(1)}`;
-}
+// /**
+//  *
+//  * @param string
+//  * @return {string}
+//  */
+// export function capitalizeFirstLetter(string: String) {
+//   return `${string.charAt(0).toUpperCase()}${string.slice(1)}`;
+// }
 
 // timestamp of last push, used to prevent local collisions if you push twice in one ms.
 let lastPushTime = 0;
@@ -296,7 +297,7 @@ export function generatePushID(serverTimeOffset?: number = 0): string {
  * @returns {Error}
  */
 export function nativeToJSError(code: string, message: string, additionalProps?: Object = {}) {
-  const error = new Error(message);
+  const error: Object = new Error(message);
   error.code = code;
   Object.assign(error, additionalProps);
   // exclude this function from the stack
@@ -310,7 +311,7 @@ export function nativeToJSError(code: string, message: string, additionalProps?:
  * @param appName
  * @param NativeModule
  */
-export function nativeWithApp(appName, NativeModule) {
+export function nativeWithApp(appName: string, NativeModule: Object) {
   const native = {};
   const methods = Object.keys(NativeModule);
 
@@ -329,7 +330,7 @@ export function nativeWithApp(appName, NativeModule) {
  * @param object
  * @return {string}
  */
-export function objectToUniqueId(object: Object): String {
+export function objectToUniqueId(object: Object): string {
   if (!isObject(object) || object === null) return JSON.stringify(object);
 
   const keys = Object.keys(object).sort();
@@ -355,7 +356,7 @@ export function objectToUniqueId(object: Object): String {
  * @param optionalCallback
  * @return {Promise}
  */
-export function promiseOrCallback(promise: Promise, optionalCallback?: Function) {
+export function promiseOrCallback(promise: Promise<*>, optionalCallback?: Function) {
   if (!isFunction(optionalCallback)) return promise;
 
   return promise.then((result) => {