index.js

'use strict';

function valueWithThousandSeparators(number) { // number is a string
  const value = Number(number);
  if (isNaN(value))
    return null;
  if (value === 0) // We don't want to transform '000' to '0', for example
    return null;
  if (value > -6000 && value < 2200) // This might be a year, which doesn't take a thousand separator
    return null;
  let result = value.toLocaleString('fr-FR');
  result = result.replace(/\s/g, '&nbsp;');
  return result;
}

function insertThousandSeparatorsWhenStartOfInput(wholeMatch, number) {
  const value = valueWithThousandSeparators(number);
  if (value === null)
    return wholeMatch;
  return value;
}

function insertThousandSeparatorsWhenBlankBefore(wholeMatch, blank, number) {
  const value = valueWithThousandSeparators(number);
  if (value === null)
    return wholeMatch;
  return blank + value;
}

function replaceSpaceWithNbsp(wholematch, space_and_punctuation, space, punctuation, quote, offset, wholeinput) {
  if (quote)
    return wholematch;
  return `&nbsp;${punctuation}`;
}

function replaceNumberAndSpaceWithNbsp(_wholeMatch, number, _space, symbol) {
  return `${number}&nbsp;${symbol}`;
}

function beautifyTextForFrench(src) {
  // This code is not very great: ideally, we should use a real parser to analyze the text and not modify anything in an hyperlink's URL, a backslashed quote, block quotes, and probably embedded HTML.
  // However, I don't have such an implementation now (and I suspect it would be near-impossible, since Markdown is quite ambiguous and not BNF).
  // Fortunately, we don't need to deal with all possible uses of Markdown, but only with MemCheck. So this implementation relies on the presence of a space char, which proves that we are not in an URL.
  // The biggest problem here is we insert thousand separators in years, which is wrong. I don't know yet how to solve that (eg question: "Combien de ml dans un l ?", answer: "1000").

  let result = src;

  // Insert thousand separators when we find a number after a space, or a space and a parenthesis
  result = result.replace(/(\s\(?)(\d+)/g, insertThousandSeparatorsWhenBlankBefore);

  // Insert thousand separators when we find a number at the begining of the text
  result = result.replace(/^(\d+)/g, insertThousandSeparatorsWhenStartOfInput);

  // White space before punctuation becomes nbsp if not in quote
  result = result.replace(/(?<space_and_punctuation>(?<space> )(?<punctuation>\?|!|;|:))|(?<quote>`.+`)/g, replaceSpaceWithNbsp);

  // Digit and white space before unit becomes nbsp
  result = result.replace(/(\d)( )(€|mm|cm|dm|m|km|l|L|hl|bar|h\/km²|°|%)/g, replaceNumberAndSpaceWithNbsp);

  return result;
}

/* exported convertMarkdown */
function convertMarkdown(src, beautifyForFrench) {
  const actualText = beautifyForFrench ? beautifyTextForFrench(src) : src;
  const converter = new showdown.Converter({ tables: true });
  converter.setOption('openLinksInNewWindow', 'true');
  converter.setOption('simplifiedAutoLink', 'true');
  converter.setOption('simpleLineBreaks', 'true');
  converter.setOption('noHeaderId', 'true');  // For size gain, even if minor
  return converter.makeHtml(actualText);
}

function buttonClicked() {
  const inputTextArea = document.getElementById('inputTextArea');
  const inputText = inputTextArea.value;

  var beautified = beautifyTextForFrench(inputText);
  var output = convertMarkdown(beautified);

  const renderedDiv = document.getElementById('renderedDiv');
  renderedDiv.innerHTML = output;
}

module.exports = beautifyTextForFrench;