unist#Position TypeScript Examples

// Helper functions

/**
 * Gets the positions of the given element type in the given text.
 * @param {string} type The element type to get positions for
 * @param {string} text The markdown text
 * @return {Position[]} The positions of the given element type in the given text
 */
function getPositions(type: string, text: string) {
  const ast = remark().use(remarkGfm).parse(text);
  const positions: Position[] = [];
  visit(ast, type, (node) => {
    positions.push(node.position);
  });

  // Sort positions by start position in reverse order
  positions.sort((a, b) => b.start.offset - a.start.offset);
  return positions;
}

/**
 * Replaces all codeblocks in the given text with a placeholder.
 * @param {string} text The text to replace codeblocks in
 * @param {string} placeholder The placeholder to use
 * @return {string} The text with codeblocks replaced, and the list of codeblocks
 * @return {string[]} The codeblocks replaced
 */
function replaceCodeblocks(text: string, placeholder: string): {text: string, replacedCodeBlocks: string[]} {
  const positions: Position[] = getPositions('code', text);
  const replacedCodeBlocks: string[] = [];

  for (const position of positions) {
    const codeblock = text.substring(position.start.offset, position.end.offset);
    replacedCodeBlocks.push(codeblock);
    text = text.substring(0, position.start.offset) + placeholder + text.substring(position.end.offset);
  }

  // Reverse the codeblocks so that they are in the same order as the original text
  replacedCodeBlocks.reverse();

  return {text, replacedCodeBlocks};
}

/**
 * Makes sure that the style of either strong or emphasis is consistent.
 * @param {string} text The text to style either the strong or emphasis in a consistent manner
 * @param {string} style The style to use for the emphasis indicator (i.e. underscore, asterisk, or consistent)
 * @param {string} type The type of element to make consistent and the value should be either strong or emphasis
 * @return {string} The text with either strong or emphasis styles made consistent
 */
export function makeEmphasisOrBoldConsistent(text: string, style: string, type: string): string {
  const positions: Position[] = getPositions(type, text);
  if (positions.length === 0) {
    return text;
  }

  let indicator = '';
  if (style === 'underscore') {
    indicator = '_';
  } else if (style === 'asterisk') {
    indicator = '*';
  } else {
    const firstPosition = positions[positions.length-1];
    indicator = text.substring(firstPosition.start.offset, firstPosition.start.offset+1);
  }

  // make the size two for the indicator when the type is strong
  if (type === 'strong') {
    indicator += indicator;
  }

  for (const position of positions) {
    text = text.substring(0, position.start.offset) + indicator + text.substring(position.start.offset + indicator.length, position.end.offset - indicator.length) + indicator + text.substring(position.end.offset);
  }

  return text;
}

/**
 * Moves footnote declarations to the end of the document.
 * @param {string} text The text to move footnotes in
 * @return {string} The text with footnote declarations moved to the end
 */
export function moveFootnotesToEnd(text: string) {
  const positions: Position[] = getPositions('footnoteDefinition', text);
  const footnotes: string[] = [];

  for (const position of positions) {
    const footnote = text.substring(position.start.offset, position.end.offset);
    footnotes.push(footnote);
    // Remove the newline after the footnote if it exists
    if (position.end.offset < text.length && text[position.end.offset] === '\n') {
      text = text.substring(0, position.end.offset) + text.substring(position.end.offset + 1);
    }
    // Remove the newline after the footnote if it exists
    if (position.end.offset < text.length && text[position.end.offset] === '\n') {
      text = text.substring(0, position.end.offset) + text.substring(position.end.offset + 1);
    }
    text = text.substring(0, position.start.offset) + text.substring(position.end.offset);
  }

  // Reverse the footnotes so that they are in the same order as the original text
  footnotes.reverse();

  // Add the footnotes to the end of the document
  if (footnotes.length > 0) {
    text = text.trimEnd() + '\n';
  }
  for (const footnote of footnotes) {
    text += '\n' + footnote;
  }

  return text;
}