readme updated

README.md

@@ -2,7 +2,7 @@
 This is a simple coupon creation project using NodeJS.
 
 [![license](https://img.shields.io/badge/license-MIT-blue.svg)](https://github.com/yusufshakeel/couponjs)
-[![npm version](https://img.shields.io/badge/npm-0.3.0-blue.svg)](https://www.npmjs.com/package/couponjs)
+[![npm version](https://img.shields.io/badge/npm-0.4.0-blue.svg)](https://www.npmjs.com/package/couponjs)
 [![Build Status](https://travis-ci.com/yusufshakeel/couponjs.svg?branch=master)](https://travis-ci.com/yusufshakeel/couponjs)
 
 # Getting Started
@@ -11,12 +11,6 @@ Add this to your project using npm.
 > npm i couponjs
 ```
 
-## Tests
-Test code of this project is inside the `tests` directory.
-
-Using the following for testing:
-* Jest
-
 ## Generate coupon
 Create an object of Coupon.
 ```javascript
@@ -32,7 +26,7 @@ const myCoupon = coupon.generate();
 
 By default, `generate` will return coupon code of length 6 using uppercase alphabet.
 
-### Coupon of length N
+## Coupon of length N
 To generate coupon of a given length we pass the following option to the `generate` method.
 ```javascript
 const myCoupon = coupon.generate({
@@ -47,7 +41,7 @@ Range of `length`:
 
 If length is not passed then default value of 6 is considered.
 
-### Coupon with prefix
+## Coupon with prefix
 To generate a coupon with a given prefix we pass the following option to the `generate` method.
 ```javascript
 const myCoupon = coupon.generate({
@@ -69,7 +63,7 @@ const myCoupon = coupon.generate({
 ```
 We will get coupon like the following `SUPERAAA`.
 
-### Coupon with suffix
+## Coupon with suffix
 To create coupon with suffix pass the following option.
 ```javascript
 const myCoupon = coupon.generate({
@@ -79,9 +73,9 @@ const myCoupon = coupon.generate({
 ```
 The above code will generate coupon like the following `ZZZAWESOME`.
 
-Note! Characters of the suffix is not counted. If length is note specified then default value of 6 is considered as the length.
+Note! Characters of the suffix is not counted. If length is not specified then default value of 6 is considered as the length.
 
-### Coupon with prefix and suffix
+## Coupon with prefix and suffix
 To create coupon with prefix and suffix pass the following option.
 ```javascript
 const myCoupon = coupon.generate({
@@ -94,6 +88,61 @@ The above code will generate coupon like the following `SUPERZZZZZZAWESOME`.
 
 Note! The characters of the prefix and suffix is not considered. If length is not specified then default value of 6 is considered.
 
+## Coupon with builtIn characterSet
+To create coupon code with builtIn characterSet pass the following option.
+```javascript
+const myCoupon = coupon.generate({
+  characterSet: {
+    builtIn: ['charSetName']
+  }
+});
+```
+Where, `charSetName` is any one of the following names.
+
+- `CHARSET_ALPHA` -- which consists of uppercase alphabet characters A-Z
+- `CHARSET_ALPHA_LOWER` -- which consists of lowercase alphabet characters a-z
+- `CHARSET_DIGIT` -- which consists of digits 0-9
+
+Example: If we want uppercase and digit we can pass the following.
+```javascript
+const myCoupon = coupon.generate({
+  characterSet: {
+    builtIn: ['CHARSET_ALPHA', 'CHARSET_DIGIT']
+  }
+});
+```
+
+## Coupon with custom characterSet
+To use custom characters to generate coupons pass the following option.
+```javascript
+const myCoupon = coupon.generate({
+  characterSet: {
+    custom: ['customChar']
+  }
+});
+```
+Where, `customChar` is any custom characters that you wish to use.
+
+Example: To use `ABC`, `xyz` and `01234` in coupon pass the following.
+```javascript
+const myCoupon = coupon.generate({
+  characterSet: {
+    custom: ['ABC', 'xyz', '01234']
+  }
+});
+```
+
+## Coupons using builtIn and custom characterSet
+Example: Following option will use digit `0-9` and alphabet `ABC`.
+```javascript
+const myCoupon = coupon.generate({
+  characterSet: {
+    builtIn: ['CHARSET_DIGIT'],
+    custom: ['ABC']
+  }
+});
+```
+
 ## License
 It's free :smiley: