StructureJS
0.15.2A class based utility library for building modular and scalable web platform applications. Features opt-in classes and utilities which provide a solid foundation and toolset to build your next project.
File: ts/util/MathUtil.ts
/**
* A helper class to do calculations and conversions.
*
* @class MathUtil
* @module StructureJS
* @submodule util
* @author Robert S. (www.codeBelt.com)
* @static
*/
class MathUtil
{
constructor()
{
throw new Error('[MathUtil] Do not instantiate the MathUtil class because it is a static class.');
}
/**
* Returns a number constrained between min and max.
*
* @method constrain
* @param num {number}
* @param min {number}
* @param max {number}
* @return {number}
* @example
* MathUtil.constrain(12, 3, 20);
* // 12
*
* MathUtil.constrain(22, 3, 20);
* // 20
*
* MathUtil.constrain(0, 3, 20);
* // 3
*/
public static constrain(num:number, min:number = 0, max:number = 1):number
{
if (num < min)
{
return min;
}
if (num > max)
{
return max;
}
return num;
}
/**
* Returns a random number between min and max.
*
* @method randomRange
* @param min {number}
* @param max {number}
* @param [wholeNumber=true] {number}
* @return {number}
* @example
*
*/
public static randomRange(min:number, max:number, wholeNumber:boolean = true):number
{
const num:number = (min + Math.random() * (max - min));
if (wholeNumber)
{
return Math.round(num);
}
return num;
}
/**
* Returns the percentage of a number in a given range.
* Example: num = 15 range 10 to 20 // outputs 0.5
*
* @method rangeToPercent
* @param num {number}
* @param min {number}
* @param max {number}
* @param constrainMin {boolean} Returns 0 if num < min.
* @param constrainMax {boolean} Returns 1 if num > max.
* @return {number}
* @example
* MathUtil.rangeToPercent(15, 10, 20);
* // 0.5
*/
public static rangeToPercent(num:number, min:number, max:number, constrainMin:boolean = false, constrainMax:boolean = false):number
{
if (constrainMin && num < min)
{
return 0;
}
if (constrainMax && num > max)
{
return 1;
}
return (num - min) / (max - min);
}
/**
* Returns the number that corresponds to the percentage in a given range.
* Example: percent = 0.5 range 10 to 20 // outputs 15
*
* @method percentToRange
* @param percent {number}
* @param min {number}
* @param max {number}
* @return {number}
* @example
* MathUtil.percentToRange(0.5, 10, 20);
* // 15
*/
public static percentToRange(percent:number, min:number, max:number):number
{
return (percent * (max - min)) + min;
}
/**
* Re-maps a number from one range to another. The output is the same as inputing the result of rangeToPercent() numbero percentToRange().
* Example: num = 10, min1 = 0, max1 = 100, min2 = 0, max2 = 50 // outputs 5
*
* @method map
* @param num {number}
* @param min1 {number}
* @param max1 {number}
* @param min2 {number}
* @param max2 {number}
* @return {number}
* @example
* MathUtil.map(10, 0, 100, 0, 50);
* // 5
*/
public static map(num:number, min1:number, max1:number, min2:number, max2:number, round:boolean = true, constrainMin:boolean = true, constrainMax:boolean = true):number
{
if (constrainMin && num < min1)
{
return min2;
}
if (constrainMax && num > max1)
{
return max2;
}
const num1:number = (num - min1) / (max1 - min1);
const num2:number = (num1 * (max2 - min2)) + min2;
if (round)
{
return Math.round(num2);
}
return num2;
}
/**
* Converts radians to degrees.
*
* @method radiansToDegrees
* @param radians {number}
* @return {number}
* @example
* MathUtil.radiansToDegrees(1.5707963267948966);
* // 90
*
* MathUtil.radiansToDegrees(3.141592653589793);
* // 180
*/
public static radiansToDegrees(radians:number):number
{
return radians * (180 / Math.PI);
}
/**
* Converts degrees to radians.
*
* @method degreesToRadians
* @param degrees {number}
* @return {number}
* @example
* MathUtil.degreesToRadians(90);
* // 1.5707963267948966
*
* MathUtil.degreesToRadians(180);
* // 3.141592653589793
*/
public static degreesToRadians(degrees:number):number
{
return (degrees * Math.PI / 180);
}
/**
* Returns 1 if the value is >= 0. Returns -1 if the value is < 0.
*
* @method sign
* @param num {number}
* @return {number}
* @example
* MathUtil.sign(23);
* // 1
*
* MathUtil.sign(-23);
* // -1
*/
public static sign(num:number):number
{
if (num < 0)
{
return -1
}
return 1;
}
/**
* Check if number is positive (zero is positive).
*
* @method isPositive
* @param num {number} The number.
* @return {boolean}
* @example
* MathUtil.isPositive(23);
* // true
*
* MathUtil.isPositive(-23);
* // false
*/
public static isPositive(num:number):boolean
{
return (num >= 0);
}
/**
* Check if number is negative.
*
* @method isNegative
* @param num {number} The
* @return {boolean}
* @example
* MathUtil.isNegative(23);
* // false
*
* MathUtil.isNegative(-23);
* // true
*/
public static isNegative(num:number):boolean
{
return (num < 0);
}
/**
* Check if number is odd (convert to Integer if necessary).
*
* @method isOdd
* @param num {number} The number.
* @return {boolean}
* @example
* MathUtil.isOdd(2);
* // false
*
* MathUtil.isOdd(3);
* // true
*/
public static isOdd(num:number):boolean
{
const i:number = num;
const e:number = 2;
return Boolean(i % e);
}
/**
* Check if number is even (convert to Integer if necessary).
*
* @method isEven
* @param num {number} The number.
* @return {boolean}
* @example
* MathUtil.isEven(2);
* // true
*
* MathUtil.isEven(3);
* // false
*/
public static isEven(num:number):boolean
{
const int:number = num;
const e:number = 2;
return (int % e == 0);
}
/**
* Check if number is Prime (divisible only by itself and one).
*
* @method isPrime
* @param num {number} The number.
* @return {boolean}
* @example
* MathUtil.isPrime(4);
* // false
*
* MathUtil.isPrime(5);
* // true
*/
public static isPrime(num:number):boolean
{
if (num > 2 && num % 2 == 0)
{
return false;
}
const l:number = Math.sqrt(num);
let i:number = 3;
for (i; i <= l; i += 2)
{
if (num % i == 0)
{
return false;
}
}
return true;
}
/**
* Calculate the factorial of the integer.
*
* @method factorial
* @param num {number} The number.
* @return {number}
* @example
* MathUtil.factorial(5);
* // 120
*
* MathUtil.factorial(9);
* // 362880
*/
public static factorial(num:number):number
{
if (num == 0)
{
return 1;
}
let d:number = <number>num.valueOf();
let i:number = d - 1;
while (i)
{
d = d * i;
i--;
}
return d;
}
/**
* Return an array of divisors of the integer.
*
* @method getDivisors
* @param num {number} The number.
* @return {Array.<number>}
* @example
*
*/
public static getDivisors(num:number):Array<number>
{
const r:Array<number> = [];
for (let i:number = 1, e:number = num / 2; i <= e; i++)
{
if (num % i == 0)
{
r.push(i);
}
}
if (num != 0)
{
r.push(<number>num.valueOf());
}
return r;
}
}
export default MathUtil;