Merge pull request phaserjs#3607 from Fabadiculous/docs

Docs for GetPhysicsPlugins, Factorial, FloatBetween and Difference

Author: photonstorm

src/math/Difference.js

@@ -5,15 +5,15 @@
  */
 
 /**
- * [description]
+ * Calculates the positive difference of two given numbers.
  *
  * @function Phaser.Math.Difference
  * @since 3.0.0
  *
- * @param {number} a - [description]
- * @param {number} b - [description]
+ * @param {number} a - The first number in the calculation.
+ * @param {number} b - The second number in the calculation.
  *
- * @return {number} [description]
+ * @return {number} The positive difference of the two given numbers.
  */
 var Difference = function (a, b)
 {

src/math/Factorial.js

@@ -5,14 +5,14 @@
  */
 
 /**
- * [description]
+ * Calculates the factorial of a given number for integer values greater than 0.
  *
  * @function Phaser.Math.Factorial
  * @since 3.0.0
  *
- * @param {number} value - [description]
+ * @param {number} value - A positive integer to calculate the factorial of.
  *
- * @return {number} [description]
+ * @return {number} The factorial of the given number.
  */
 var Factorial = function (value)
 {

src/math/FloatBetween.js

@@ -5,15 +5,15 @@
  */
 
 /**
- * [description]
+ * Generate a random floating point number between the two given bounds, minimum inclusive, maximum exclusive.
  *
  * @function Phaser.Math.FloatBetween
  * @since 3.0.0
  *
- * @param {float} min - [description]
- * @param {float} max - [description]
+ * @param {float} min - The lower bound for the float, inclusive.
+ * @param {float} max - The upper bound for the float exclusive.
  *
- * @return {float} [description]
+ * @return {float} A random float within the given range.
  */
 var FloatBetween = function (min, max)
 {

src/scene/GetPhysicsPlugins.js

@@ -13,9 +13,9 @@ var UppercaseFirst = require('../utils/string/UppercaseFirst');
  * @function Phaser.Scenes.GetPhysicsPlugins
  * @since 3.0.0
  *
- * @param {Phaser.Scenes.Systems} sys - [description]
+ * @param {Phaser.Scenes.Systems} sys - The scene system to get the physics systems of.
  *
- * @return {array} [description]
+ * @return {array} An array of Physics systems to start for this Scene.
  */
 var GetPhysicsPlugins = function (sys)
 {