difference-engine

Difference Engine

npm i -P difference-engine

Features are available as static methods on the class:

import DifferenceEngine from 'difference-engine'

And as functions exported from the module:

import {
  inclusive,
  exclusive
} from 'difference-engine'

Examples use the static form.

inclusive

Accepts two arrays. Returns an array containing items which appear in both arrays.

const alpha = ['A', 'B', 'C']
const omega = ['C', 'D', 'E']

const array = DifferenceEngine.inclusive(alpha, omega) // returns ['C']

exclusive

Accepts two arrays. Returns an array containing items which appear in the first array but not the second.

const alpha = ['A', 'B', 'C']
const omega = ['C', 'D', 'E']

const array = DifferenceEngine.exclusive(alpha, omega) // returns ['A', 'B']

ArrayEngine

Features are available as static methods on the class:

import { ArrayEngine } from 'difference-engine'

And as functions exported from the module:

import ArrayEngine, {
  indexOf,
  iterateForward,
  iterateReverse,
  iterateBetween,
  max,
  min,
  bite
} from 'difference-engine/array-engine'

Examples use the static form.

indexOf

const array = ['A', 'B', 'C', 'D', 'E']

const index = ArrayEngine.indexOf(array, 'E') // returns 4

bite

Accepts an array and two indexes. Returns a slice from the array.

Positive

const alpha = ['A', 'B', 'C', 'D', 'E']

const omega = ArrayEngine.bite(alpha, 0, 0) // returns ['A']

const alpha = ['A', 'B', 'C', 'D', 'E']

const omega = ArrayEngine.bite(alpha, 0, 4) // returns ['A', 'B', 'C', 'D', 'E']

const alpha = ['A', 'B', 'C', 'D', 'E']

const omega = ArrayEngine.bite(alpha, 4, 0) // returns ['E', 'D', 'C', 'B', 'A']

const alpha = ['A', 'B', 'C', 'D', 'E']

const omega = ArrayEngine.bite(alpha, 4, 4) // returns ['E']

Negative

const alpha = ['A', 'B', 'C', 'D', 'E']

const omega = ArrayEngine.bite(alpha, -4, 0) // returns ['A']

const alpha = ['A', 'B', 'C', 'D', 'E']

const omega = ArrayEngine.bite(alpha, -4, 4) // returns ['A', 'B', 'C', 'D', 'E']

const alpha = ['A', 'B', 'C', 'D', 'E']

const omega = ArrayEngine.bite(alpha, -4, -4) // returns ['E', 'D', 'C', 'B', 'A']

const alpha = ['A', 'B', 'C', 'D', 'E']

const omega = ArrayEngine.bite(alpha, 4, -4) // returns ['E', 'D', 'C', 'B', 'A']

const alpha = ['A', 'B', 'C', 'D', 'E']

const omega = ArrayEngine.bite(alpha, 0, -4) // returns ['A']

iterateForward

Accepts an array and a function. Iterates from start to end.

const array = ['A', 'B', 'C', 'D', 'E']

ArrayEngine.iterateForward(array, () => {})

iterateReverse

Accepts an array and a function. Iterates from end to start.

const array = ['A', 'B', 'C', 'D', 'E']

ArrayEngine.iterateReverse(array, () => {})

iterateBetween

Accepts an array, a start index, an end index, and a function.

If the first index is less than the second index, it behaves as iterateForward.

If the first index is greater than the second index, it behaves as iterateReverse.

const array = ['A', 'B', 'C', 'D', 'E']

ArrayEngine.iterateBetween(array, 1, 3, () => {})

max

Accepts an array. Returns the largest item (when compared as a number).

const array = ['A', 'B', 'C', 'D', 'E']

const value = ArrayEngine.max(array) // returns 'E'

const array = [1, 2, 3, 4, 5]

const value = ArrayEngine.max(array) // returns 5

min

Accepts an array. Returns the smallest item (when compared as a number).

const array = ['A', 'B', 'C', 'D', 'E']

const value = ArrayEngine.min(array) // returns 'A'

const array = [1, 2, 3, 4, 5]

const value = ArrayEngine.min(array) // returns 1

NumberEngine

Features are available as static methods on the class:

import { NumberEngine } from 'difference-engine'

And as functions exported from the module:

import NumberEngine, {
  fibonacci,
  haversine,
  fromOctToDec,
  fromHexToDec,
  Weight,
  Temperature,
  Distance
} from 'difference-engine/number-engine'

Examples use the static form.

fibonacci

Accepts an index. Returns the number in a Fibonacci sequence corresponding to the index.

const fibonacci = NumberEngine.fibonacci(0) // returns 0

const fibonacci = NumberEngine.fibonacci(1) // returns 1

const fibonacci = NumberEngine.fibonacci(2) // returns 1

const fibonacci = NumberEngine.fibonacci(3) // returns 2

haversine

Accepts an object with fields describing latitude and longitude points from and to.

Returns a value in kilometres or miles.

const points = { from: { lat: 51.4934, lng: 0.0098 }, to: { lat: 40.7128, lng: 74.0060 } }

const km = NumberEngine.haversine(points).km() // returns the distance in kilometres
const mi = NumberEngine.haversine(points).mi() // returns the distance in miles

fromOctToDec

Accepts a string representing an octal. Returns a decimal.

const dec = NumberEngine.fromOctToDec('20') // returns 16

fromHexToDec

Accepts a string representing a hexadecimal. Returns a decimal.

const dec = NumberEngine.fromHexToDec('10') // returns 16

Weight

Convert a number from one unit to another.

As static methods on the class:

import { NumberEngine: { Weight } } from 'difference-engine'

And as functions exported from the module:

import Weight, {
  fromKgToGr,
  fromKgToMg,
  fromKgToOz,
  fromKgToLb,
  fromKgToSt,

  fromGrToKg,
  fromGrToMg,
  fromGrToOz,
  fromGrToLb,
  fromGrToSt,

  fromMgToKg,
  fromMgToGr,
  fromMgToOz,
  fromMgToLb,
  fromMgToSt,

  fromOzToKg,
  fromOzToGr,
  fromOzToMg,
  fromOzToLb,
  fromOzToSt,

  fromLbToKg,
  fromLbToGr,
  fromLbToMg,
  fromLbToOz,
  fromLbToSt,

  fromStToKg,
  fromStToGr,
  fromStToMg,
  fromStToLb,
  fromStToOz,

  convert
} from 'difference-engine/number-engine/weight'

Examples use the static form.

Kilogram

const gr = Weight.fromKgToGr(10)

const mg = Weight.fromKgToMg(10)

const oz = Weight.fromKgToOz(10)

const lb = Weight.fromKgToLb(10)

const st = Weight.fromKgToSt(10)

Or, using convert.

const gr = Weight.convert(10).fromKg.toGr()

const mg = Weight.convert(10).fromKg.toMg()

const oz = Weight.convert(10).fromKg.toOz()

const lb = Weight.convert(10).fromKg.toLb()

const st = Weight.convert(10).fromKg.toSt()

Gram

const kg = Weight.fromGrToKg(10)

const mg = Weight.fromGrToMg(10)

const oz = Weight.fromGrToOz(10)

const lb = Weight.fromGrToLb(10)

const st = Weight.fromGrToSt(10)

Or, using convert.

const kg = Weight.convert(10).fromGr.toKg()

const mg = Weight.convert(10).fromGr.toMg()

const oz = Weight.convert(10).fromGr.toOz()

const lb = Weight.convert(10).fromGr.toLb()

const st = Weight.convert(10).fromGr.toSt()

Miligram

const kg = Weight.fromMgToKg(10)

const gr = Weight.fromMgToGr(10)

const oz = Weight.fromMgToOz(10)

const lb = Weight.fromMgToLb(10)

const st = Weight.fromMgToSt(10)

Or, using convert.

const kg = Weight.convert(10).fromMg.toKg()

const gr = Weight.convert(10).fromMg.toGr()

const oz = Weight.convert(10).fromMg.toOz()

const lb = Weight.convert(10).fromMg.toLb()

const st = Weight.convert(10).fromMg.toSt()

Ounce

const kg = Weight.fromOzToKg(10)

const gr = Weight.fromOzToGr(10)

const mg = Weight.fromOzToMg(10)

const lb = Weight.fromOzToLb(10)

const st = Weight.fromOzToSt(10)

Or, using convert.

const kg = Weight.convert(10).fromOz.toKg()

const gr = Weight.convert(10).fromOz.toGr()

const mg = Weight.convert(10).fromOz.toMg()

const lb = Weight.convert(10).fromOz.toLb()

const st = Weight.convert(10).fromOz.toSt()

Pound

const kg = Weight.fromLbToKg(10)

const gr = Weight.fromLbToGr(10)

const mg = Weight.fromLbToMg(10)

const oz = Weight.fromLbToOz(10)

const st = Weight.fromLbToSt(10)

Or, using convert.

const kg = Weight.convert(10).fromLb.toKg()

const gr = Weight.convert(10).fromLb.toGr()

const mg = Weight.convert(10).fromLb.toMg()

const oz = Weight.convert(10).fromLb.toOz()

const st = Weight.convert(10).fromLb.toSt()

Stone

const kg = Weight.fromStToKg(10)

const gr = Weight.fromStToGr(10)

const mg = Weight.fromStToMg(10)

const lb = Weight.fromStToLb(10)

const oz = Weight.fromStToOz(10)

Or, using convert.

const kg = Weight.convert(10).fromSt.toKg()

const gr = Weight.convert(10).fromSt.toGr()

const mg = Weight.convert(10).fromSt.toMg()

const lb = Weight.convert(10).fromSt.toLb()

const oz = Weight.convert(10).fromSt.toOz()

Temperature

Convert a number from one unit to another.

As static methods on the class:

import { NumberEngine: { Temperature } } from 'difference-engine'

And as functions exported from the module:

import Temperature, {
  fromCToF,
  fromFToC
} from 'difference-engine/number-engine/temperature'

Examples use the static form.

const value = Temperature.fromCToF(10)

const value = Temperature.fromFToC(10)

Distance

Convert a number from one unit to another.

As static methods on the class:

import { NumberEngine: { Distance } } from 'difference-engine'

And as functions exported from the module:

import Distance, {
  fromKmToMt,
  fromKmToCm,
  fromKmToMm,
  fromKmToIn,
  fromKmToFt,
  fromKmToYd,
  fromKmToMi,

  fromMtToKm,
  fromMtToCm,
  fromMtToMm,
  fromMtToIn,
  fromMtToFt,
  fromMtToYd,
  fromMtToMi,

  fromCmToKm,
  fromCmToMt,
  fromCmToMm,
  fromCmToIn,
  fromCmToFt,
  fromCmToYd,
  fromCmToMi,

  fromMmToKm,
  fromMmToMt,
  fromMmToCm,
  fromMmToIn,
  fromMmToFt,
  fromMmToYd,
  fromMmToMi,

  fromInToKm,
  fromInToMt,
  fromInToCm,
  fromInToMm,
  fromInToFt,
  fromInToYd,
  fromInToMi,

  fromFtToKm,
  fromFtToMt,
  fromFtToCm,
  fromFtToMm,
  fromFtToIn,
  fromFtToYd,
  fromFtToMi,

  fromYdToKm,
  fromYdToMt,
  fromYdToCm,
  fromYdToMm,
  fromYdToIn,
  fromYdToFt,
  fromYdToMi,

  fromMiToKm,
  fromMiToMt,
  fromMiToCm,
  fromMiToMm,
  fromMiToIn,
  fromMiToFt,
  fromMiToYd,

  convert
} from 'difference-engine/number-engine/distance'

Examples use the static form.

Kilometre

const mt = Distance.fromKmToMt(10)

const cm = Distance.fromKmToCm(10)

const mm = Distance.fromKmToMm(10)

const in = Distance.fromKmToIn(10)

const ft = Distance.fromKmToFt(10)

const yd = Distance.fromKmToYd(10)

const mi = Distance.fromKmToMi(10)

Or, using convert.

const mt = Distance.convert(10).fromKm.toMt()

const cm = Distance.convert(10).fromKm.toCm()

const mm = Distance.convert(10).fromKm.toMm()

const in = Distance.convert(10).fromKm.toIn()

const ft = Distance.convert(10).fromKm.toFt()

const yd = Distance.convert(10).fromKm.toYd()

const mi = Distance.convert(10).fromKm.toMi()

Metre

const km = Distance.fromMtToKm(10)

const cm = Distance.fromMtToCm(10)

const mm = Distance.fromMtToMm(10)

const in = Distance.fromMtToIn(10)

const ft = Distance.fromMtToFt(10)

const yd = Distance.fromMtToYd(10)

const mi = Distance.fromMtToMi(10)

Or, using convert.

const km = Distance.convert(10).fromMt.toKm()

const cm = Distance.convert(10).fromMt.toCm()

const mm = Distance.convert(10).fromMt.toMm()

const in = Distance.convert(10).fromMt.toIn()

const ft = Distance.convert(10).fromMt.toFt()

const yd = Distance.convert(10).fromMt.toYd()

const mi = Distance.convert(10).fromMt.toMi()

Centimetre

const km = Distance.fromCmToKm(10)

const mt = Distance.fromCmToMt(10)

const mm = Distance.fromCmToMm(10)

const in = Distance.fromCmToIn(10)

const ft = Distance.fromCmToFt(10)

const yd = Distance.fromCmToYd(10)

const mi = Distance.fromCmToMi(10)

Or, using convert.

const km = Distance.convert(10).fromCm.toKm()

const mt = Distance.convert(10).fromCm.toMt()

const mm = Distance.convert(10).fromCm.toMm()

const in = Distance.convert(10).fromCm.toIn()

const ft = Distance.convert(10).fromCm.toFt()

const yd = Distance.convert(10).fromCm.toYd()

const mi = Distance.convert(10).fromCm.toMi()

Milimetre

const km = Distance.fromMmToKm(10)

const mt = Distance.fromMmToMt(10)

const cm = Distance.fromMmToCm(10)

const in = Distance.fromMmToIn(10)

const ft = Distance.fromMmToFt(10)

const yd = Distance.fromMmToYd(10)

const mi = Distance.fromMmToMi(10)

Or, using convert.

const km = Distance.convert(10).fromMm.toKm()

const mt = Distance.convert(10).fromMm.toMt()

const cm = Distance.convert(10).fromMm.toCm()

const in = Distance.convert(10).fromMm.toIn()

const ft = Distance.convert(10).fromMm.toFt()

const yd = Distance.convert(10).fromMm.toYd()

const mi = Distance.convert(10).fromMm.toMi()

Inch

const km = Distance.fromInToKm(10)

const mt = Distance.fromInToMt(10)

const cm = Distance.fromInToCm(10)

const mm = Distance.fromInToMm(10)

const ft = Distance.fromInToFt(10)

const yd = Distance.fromInToYd(10)

const mi = Distance.fromInToMi(10)

Or, using convert.

const km = Distance.convert(10).fromIn.toKm()

const mt = Distance.convert(10).fromIn.toMt()

const cm = Distance.convert(10).fromIn.toCm()

const mm = Distance.convert(10).fromIn.toMm()

const ft = Distance.convert(10).fromIn.toFt()

const yd = Distance.convert(10).fromIn.toYd()

const mi = Distance.convert(10).fromIn.toMi()

Feet

const km = Distance.fromFtToKm(10)

const mt = Distance.fromFtToMt(10)

const cm = Distance.fromFtToCm(10)

const mm = Distance.fromFtToMm(10)

const in = Distance.fromFtToIn(10)

const yd = Distance.fromFtToYd(10)

const mi = Distance.fromFtToMi(10)

Or, using convert.

const km = Distance.convert(10).fromFt.toKm()

const mt = Distance.convert(10).fromFt.toMt()

const cm = Distance.convert(10).fromFt.toCm()

const mm = Distance.convert(10).fromFt.toMm()

const in = Distance.convert(10).fromFt.toIn()

const yd = Distance.convert(10).fromFt.toYd()

const mi = Distance.convert(10).fromFt.toMi()

Yard

const km = Distance.fromYdToKm(10)

const mt = Distance.fromYdToMt(10)

const cm = Distance.fromYdToCm(10)

const mm = Distance.fromYdToMm(10)

const in = Distance.fromYdToIn(10)

const ft = Distance.fromYdToFt(10)

const mi = Distance.fromYdToMi(10)

Or, using convert.

const km = Distance.convert(10).fromYd.toKm()

const mt = Distance.convert(10).fromYd.toMt()

const cm = Distance.convert(10).fromYd.toCm()

const mm = Distance.convert(10).fromYd.toMm()

const in = Distance.convert(10).fromYd.toIn()

const ft = Distance.convert(10).fromYd.toFt()

const mi = Distance.convert(10).fromYd.toMi()

Mile

const km = Distance.fromMiToKm(10)

const mt = Distance.fromMiToMt(10)

const cm = Distance.fromMiToCm(10)

const mm = Distance.fromMiToMm(10)

const in = Distance.fromMiToIn(10)

const ft = Distance.fromMiToFt(10)

const yd = Distance.fromMiToYd(10)

Or, using convert.

const km = Distance.convert(10).fromMi.toKm()

const mt = Distance.convert(10).fromMi.toMt()

const cm = Distance.convert(10).fromMi.toCm()

const mm = Distance.convert(10).fromMi.toMm()

const in = Distance.convert(10).fromMi.toIn()

const ft = Distance.convert(10).fromMi.toFt()

const yd = Distance.convert(10).fromMi.toYd()

StringEngine

import { StringEngine } from 'difference-engine'

charAt

Accepts a string and a number which is an index. Returns the character for the entity at the index.

const string = StringEngine.charAt('Hello, World', 5) // returns ','

const string = StringEngine.charAt('Hello, World', 5) // returns ','

charCodeAt

Accepts a string and a number which is an index. Returns the character code for the entity at the index.

const number = StringEngine.charCodeAt('Hello, World', 5) // returns 44

const number = StringEngine.charCodeAt('Hello, World', 5) // returns 44

charOf

Accepts a string which is an HTML entity. Returns the character for the entity.

const string = StringEngine.charOf(',') // returns ','

const string = StringEngine.charOf(',') // returns ','

charCodeOf

Accepts a string which is an HTML entity. Returns the character code for the entity.

const number = StringEngine.charCodeOf(',') // returns 44

const number = StringEngine.charCodeOf(',') // returns 44

entityAt

Accepts a string and a number which is an index.

Where the character at the index is an entity, it returns the entity.

const string = StringEngine.entityAt('Hello, World', 5) // returns ','

const string = StringEngine.entityAt('Hello, World', 6) // returns ' '

Where the character at the index has an entity name, it returns the entity name.

const string = StringEngine.entityAt('Hello, World', 5) // returns ','

Where the character at the index has an entity code, it returns the entity code.

const string = StringEngine.entityAt('Hello, World', 6) // returns ' '

entityCodeAt

Accepts a string and a number which is an index.

Where the character at the index has an entity code, it returns the entity code.

const string = StringEngine.entityCodeAt('Hello, World', 5) // returns ','

Where the character at the index is an entity code, it returns the entity code.

const string = StringEngine.entityCodeAt('Hello, World', 5) // returns ','

Where the character at the index is an entity name, it returns the entity code for the char at the index.

const string = StringEngine.entityCodeAt('Hello, World', 5) // returns '&'

entityNameAt

Accepts a string and a number which is an index.

Where the character at the index has an entity name, it returns the entity name.

const string = StringEngine.entityNameAt('Hello, World', 5) // returns ','

Where the character at the index is an entity name, it returns the entity name.

const string = StringEngine.entityNameAt('Hello, World', 5) // returns ','

Where the character at the index is an entity code, it returns the entity name for the char at the index.

const string = StringEngine.entityNameAt('Hello, World', 5) // returns '&'

entityOf

Accepts a string and a number which is an index.

Where the character at the index is an entity, it returns the entity.

const string = StringEngine.entityOf(',') // returns ','

const string = StringEngine.entityOf(' ') // returns ' '

fromCodePoint

Accepts a number which is a character code point. Returns the character for that code point.

const string = StringEngine.fromCodePoint(43) // returns '+'

charFromEntityCode

Accepts a string which is an HTML entity code. Returns the character for that entity.

const string = StringEngine.charFromEntityCode('+') // returns '+'

charFromEntityName

Accepts a string which is an HTML entity name. Returns the character for that entity.

const string = StringEngine.charFromEntityCode('+') // returns '+'

toEntityCode

Accepts a string. Returns a string replaced with the HTML entity code for each character.

const string = StringEngine.toEntityCode('Hello, World') // returns 'Hello, World'

toEntityName

Accepts a string. Returns a string replaced with the HTML entity name for each character where it is known, otherwise the character is not replaced.

const string = StringEngine.toEntityName('Hello, World') // returns 'Hello, World'

entityCodeFromChar

Accepts a single-character string. Returns a string representing the HTML entity code for that character.

const entityCode = StringEngine.entityCodeFromChar('+') // returns '+'

The entity is computed from the character code point.

entityNameFromChar

Accepts a single-character string. Returns a string representing the HTML entity code for that character.

const entityName = StringEngine.entityNameFromChar('+') // returns '+'

Where the character has no entity or the entity is not known it returns the character.

entityCodeOf

See entityCodeFromChar.

entityNameOf

See entityNameFromChar.

fromDecToOct

Accepts number. Returns a string representing an octal.

const oct = StringEngine.fromDecToOct(16) // returns '20'

fromDecToHex

Accepts number. Returns a string representing a hexadecimal.

const hex = StringEngine.fromDecToHex(16) // returns '10'

reverse

Accepts a string. Returns the string with characters in reverse order.

const string = StringEngine.reverse('ABCDE') // returns 'EDCBA'