mocking-text.ts

/**
 * from https://stackoverflow.com/a/49434653
 */
export const boxMullerTransformedRand = (): number => {
  let u = 0, v = 0
  while (u === 0) u = Math.random() //Converting [0,1) to (0,1)
  while (v === 0) v = Math.random()
  let num = Math.sqrt(-2.0 * Math.log(u)) * Math.cos(2.0 * Math.PI * v)
  num = num / 10.0 + 0.5 // Translate to 0 -> 1
  if (num > 1 || num < 0) return boxMullerTransformedRand() // resample between 0 and 1
  return num
}

const chars = `englishisawestgermaniclanguagethatwasfirstspokeninearlymedievalenglandandeventuallybecameagloballinguafrancaitisnamedaftertheanglesoneofthegermanictribesthatmigratedtotheareaofgreatbritainthatlatertooktheirnameenglandbothnamesderivefromangliaapeninsulaonthebalticseaenglishismostcloselyrelatedtofrisianandlowsaxonwhileitsvocabularyhasbeensignificantlyinfluencedbyothergermaniclanguagesparticularlynorseanorthgermaniclanguageaswellaslatinandfrenchenglishhasdevelopedoverthecourseofmorethanyearstheearliestformsofenglishagroupofwestgermanicingvaeonicdialectsbroughttogreatbritainbyanglosaxonsettlersinthethcenturyarecollectivelycalledoldenglishmiddleenglishbeganinthelatethcenturywiththenormanconquestofenglandthiswasaperiodinwhichenglishwasinfluencedbyoldfrenchinparticularthoughitsoldnormandialectearlymodernenglishbeganinthelatethcenturywiththeintroductionoftheprintingpresstolondontheprintingofthekingjamesbibleandthestartofthegreatvowelshift`
const symbols = '....??:!'

export const randomChar = (collection = chars) => (
  collection[Math.floor(Math.random() * collection.length)]
)

export const randomWord = () => {
  const len: number = Math.ceil(boxMullerTransformedRand() * 10) + 1
  const arr = new Array(len)

  for (let i = 0; i < len; i++) {
    arr[i] = randomChar()
  }

  return arr.join('')
}

export const randomSentence = () => {
  const len = Math.floor(Math.random() * 15) + 3
  const arr = new Array(len)

  for (let i = 0; i < len; i++) {
    arr[i] = randomWord()
  }

  const sentance = arr.join(' ')

  return sentance[0].toUpperCase() + sentance.substring(1)
}

export const randomParagraph = () => {
  const len = Math.floor(Math.random() * 8) + 2
  const arr = new Array(len)

  for (let i = 0; i < len; i++) {
    arr[i] = randomSentence()
  }

  return arr.map(str => str + randomChar(symbols)).join(' ')
}