math

@typed/math -- 3.0.0

Math related functions

Get it

yarn add @typed/math
# or
npm install --save @typed/math

API Documentation

All functions are curried!

add(x: number, y: number): number

Add 2 numbers together

See the code

export const add = curry2(__add)

function __add(x: number, y: number): number {
  return x + y
}

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decrement(num: number): number

Subtracts 1 from a number.

See the code

export const decrement = add(-1)

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divide(x: number, y: number): number

Divides 2 numbers

See the code

export const divide = curry2(__divide)

function __divide(right: number, left: number): number {
  return left / right
}

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increment(num: number): number

Adds 1 to a number.

See the code

export const increment = add(1)

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mean(numbers: List<number>): number

Calculates the average of a list of numbers.

See the code

export const mean = (numbers: List<number>) => divide(numbers.length, sum(numbers))

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median(numbers: List<number>): Maybe<number>

Calculates the median of a List. If the calculated median is NaN a Nothing is returned otherwise a Just containing the median will be returned.

See the code

export function median(numbers: List<number>): Maybe<number> {
  const length = numbers.length

  if (length === 0) return Nothing

  const width = 2 - (length % 2)
  const index = (length - width) / 2

  const medianNumbers = slice(index, Maybe.of(index + width), sort<number>(ascend(x => x), numbers))

  return numberToMaybe(mean(medianNumbers))
}

function numberToMaybe(num: number): Maybe<number> {
  return Number.isNaN(num) ? Nothing : Maybe.of(num)
}

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modulo(right: number, left: number): number

Applies % to 2 numbers.

See the code

export const modulo = curry2(__modulo)

function __modulo(right: number, left: number): number {
  return left % right
}

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multiply(x: number, y: number): number

Multiplies 2 numbers.

See the code

export const multiply = curry2(__multiply)

function __multiply(x: number, y: number): number {
  return x * y
}

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negate(n: number): number

Negates a number.

See the code

export const negate = (n: number): number => -n

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pow(exponent: number, base: number): number

Applies a base to the exponent power.

See the code

export const pow: Pow = curry2(__pow)

export type Pow = {
  (exponent: number, base: number): number
  (exponent: number): (base: number) => number
}

function __pow(exponent: number, base: number): number {
  return Math.pow(base, exponent)
}

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produce(numbers: List<number>): number

Calculates the produce of a list of numbers.

See the code

export const product: (numbers: List<number>) => number = reduce(multiply, 1)

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subtract(right: number, left: number): number

Subtracts one number from another.

See the code

export const subtract = curry2(__subtract)

function __subtract(right: number, left: number): number {
  return left - right
}

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sum(number: List<number>): number

Adds together all of the numbers in a list.

See the code

export const sum: (numbers: List<number>) => number = reduce(add, 0)

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