@instructure/quiz-interactions/src/components/fill_blank/helpers/punctuation.js

A React UI component Library for quiz interaction types.

// Some punctuation needs to be grouped/rendered with the blank
// so it does not get awkwardly separated by a line break.

// NOTE: these lists of punctuation are likely incomplete for full i18n support
// all "ending" punctuation symbols at beginning of string until whitespace or end of string
// e.g `, and flowers` (the comma is considered "ending" punctuation)
const ENDING_PUNCTUATION_REGEX =
  /^[,，、.:：;；!！?？%‰"”'’`′″‴\]］】)）}>»›」﹂』…⋯᠁ฯ》〉。]*(\s|$)/g
// all "starting" punctuation at end of string following whitespace or start of string
// e.g. `John said, "` (the opening quote is considered "starting" punctuation)
const STARTING_PUNCTUATION_REGEX = /(\s|^)["“'‘`[［【(（{<«‹「﹁『《〈¿¡]*$/g

export const trimPunctuation = (stemItem, stemItems) => {
  // Trim all punctuation that will be grouped/rendered with the blank.
  // e.g. Fill in the _____. (group the period with the blank)
  // e.g. Complete the quote: "_____ wrongs don't make a right." (group the opening quote with the blank)
  const isFirstStemItem = stemItem.position === 1
  const isLastStemItem = stemItem.position === stemItems.length
  const initialValue = stemItem.value || ''
  // trim "ending" punctuation symbols from start of string (unless first item)
  const endingsTrimmed = isFirstStemItem
    ? initialValue.trim()
    : initialValue.trim().replace(ENDING_PUNCTUATION_REGEX, '')
  // trim "starting" punctuation symbols from end of string (unless last item)
  const startsTrimmed = isLastStemItem
    ? endingsTrimmed
    : endingsTrimmed.replace(STARTING_PUNCTUATION_REGEX, '')
  return startsTrimmed
}

export const getTrimmedPunctuation = (stemItem, stemItems) => {
  const nextStemItem = stemItems.find(si => si.position === stemItem.position + 1)
  const nextStemItemValue = nextStemItem && nextStemItem.value
  const endPunctuationMatch =
    nextStemItemValue && nextStemItemValue.trim().match(ENDING_PUNCTUATION_REGEX)
  const endPunctuation = endPunctuationMatch ? endPunctuationMatch[0] : ''

  const prevStemItem = stemItems.find(si => si.position === stemItem.position - 1)
  const prevStemItemValue = prevStemItem && prevStemItem.value
  const startPunctuationMatch =
    prevStemItemValue && prevStemItemValue.trim().match(STARTING_PUNCTUATION_REGEX)
  const startPunctuation = startPunctuationMatch ? startPunctuationMatch[0] : ''

  return {start: startPunctuation, end: endPunctuation}
}