adds block about angular low-level functions

Update README.md

Update README.md

Addressed comments made in johnpapa#768

Low level functions: added code samples and more why's

Author: sergiocruz

a1/README.md

@@ -56,6 +56,7 @@ While this guide explains the *what*, *why* and *how*, I find it helpful to see
   1. [Routing](#routing)
   1. [Task Automation](#task-automation)
   1. [Filters](#filters)
+  1. [Low Level Functions](#low-level-functions)
   1. [Angular Docs](#angular-docs)
 
 ## Single Responsibility
@@ -3268,6 +3269,95 @@ Use [Gulp](http://gulpjs.com) or [Grunt](http://gruntjs.com) for creating automa
 
 **[Back to top](#table-of-contents)**
 
+## Low Level Functions
+
+Angular 1.x ships with some [helper functions](https://docs.angularjs.org/api/ng/function) that are found within JavaScript natively. In such cases we should favor usage of native JavaScript functions instead of Angular's helper functions. In other cases where functionality is not found in JavaScript natively, we should turn to utility libraries such as [lodash](https://lodash.com/docs) to fill-in the gaps.
+
+###### [Style [Y500](#style-y500)]
+
+  - Avoid using Angular low-level functions such as `angular.copy()`, `angular.extend()` or even `angular.isUndefined()`.
+
+  *Why?*: You can replace a lot Angular's low-level functions with native ES2015+ functionality such as [`Object.assign()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/assign) for copying objects and the [Spread Syntax](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_operator#Copy_an_array) for copying arrays _(ie. `[...arr1]`)_.
+
+  *Why?*: Because this is functionality that has been made available in the latest versions of JavaScript, but did not exist natively back when helper functions were first written.
+
+  Replace `angular.forEach()` and `angular.isArray()`:
+
+  ```javascript
+  /* avoid */
+  var arr = [1, 2, 3];
+  var obj = { hello: 'Hello', world: 'World' };
+
+  angular.forEach(arr, function(value) {
+    console.log(value);
+  });
+
+  angular.forEach(obj, function(value) {
+    console.log(value);
+  });
+
+  angular.isArray(arr); // true
+  angular.isArray(obj); // false
+  ```
+
+  ```javascript
+  /* recommended */
+  var arr = [1, 2, 3];
+  var obj = { hello: 'Hello', world: 'World' };
+
+  // iterate through arrays
+  arr.forEach(function(value) {
+    console.log(value);
+  });
+
+  // iterate through objects
+  Object.keys(obj)
+    .forEach(function(key) {
+      console.log(obj[key]);
+    });
+
+  // alternative lodash helper to iterate through objects
+  _.forEach(obj, function(value) {
+    console.log(value);
+  });
+
+  // available in ES
+  Array.isArray(arr); // true
+  Array.isArray(obj); // false
+  ```
+
+  Don't use `angular.copy()` and `angular.extend()` in favor of ES2015 features:
+
+  ```javascript
+  /* avoid */
+  var arr1 = [1, 2, 3];
+  var arr2 = angular.copy(arr1); // [1, 2, 3]
+
+  var obj1 = { hello: 'Hello' };
+  var obj2 = { world: 'World' };
+  var obj3 = angular.extend({}, obj1, obj2); // {hello: 'Hello', world: 'World'}
+  ```
+
+  ```javascript
+  /* recommended */
+  var arr1 = [1, 2, 3];
+  var arr2 = [...arr1]; // [1, 2, 3]
+
+  var obj1 = { hello: 'Hello' };
+  var obj2 = { world: 'World' };
+  var obj3 = Object.assign({}, obj1, obj2); // {hello: 'Hello', world: 'World'}
+  ```
+
+  *Why?*: These are commonly known features of JavaScript and makes code more intuitive to read.
+
+  *Why?*: This will ease the process of upgrading to Angular 2 as it does not ship with these helper functions.
+
+  - Note: Favor usage of functions that are available in JavaScript natively, then resort to using a utility library like [lodash](https://lodash.com/docs) when what you need is not available.
+
+  - Note: you might need to use a [polyfill](https://babeljs.io/docs/usage/polyfill/) to take advantage the latest features of JavaScript for better browser support.
+
+**[Back to top](#table-of-contents)**
+
 ## Filters
 
 ###### [Style [Y420](#style-y420)]