Function processHighlighting

docs/src/preprocess/include_code.js:11–79

* Search for lines of the form

(codeSnippet, identifier)

 * Search for lines of the form
 */
function processHighlighting(codeSnippet, identifier) {
  const lines = codeSnippet.split("\n");
  /**
   * For an identifier = bar:
   *
   * Matches of the form: `highlight-next-line:foo:bar:baz` will be replaced with "highlight-next-line".
   * Matches of the form: `highlight-next-line:foo:baz` will be replaced with "".
   */
  const regex1 = /highlight-next-line:([a-zA-Z0-9-._:]+)/;
  const replacement1 = "highlight-next-line";
  const regex2 = /highlight-start:([a-zA-Z0-9-._:]+)/;
  const replacement2 = "highlight-start";
  const regex3 = /highlight-end:([a-zA-Z0-9-._:]+)/;
  const replacement3 = "highlight-end";
  const regex4 = /this-will-error:([a-zA-Z0-9-._:]+)/;
  const replacement4 = "this-will-error";

  let mutated = false;

  const processLine = (line, regex, replacement) => {
    const match = line.match(regex);
    if (match) {
      mutated = true;

      const identifiers = match[1].split(":");
      if (identifiers.includes(identifier)) {
        line = line.replace(match[0], replacement);
      } else {
        // Remove matched text completely
        line = line.replace(match[0], "");
      }
    } else {
      // No match: it's an ordinary line of code.
    }
    return line.trim() == "//" || line.trim() == "#" ? "" : line;
  };

  const countLeadingSpaces = (line) => {
    const match = line.match(/^ */);
    return match ? match[0].length : 0;
  };
  let indention = 200;
  let resultLines = [];

  for (let line of lines) {
    mutated = false;
    line = processLine(line, regex1, replacement1);
    line = processLine(line, regex2, replacement2);
    line = processLine(line, regex3, replacement3);
    line = processLine(line, regex4, replacement4);

    if (!(line === "" && mutated)) {
      resultLines.push(line);

      const leadingSpaces = countLeadingSpaces(line);
      if (line.length > 0 && leadingSpaces < indention) {
        indention = leadingSpaces;
      }