MZC/KnowMathBot/frontend/node_modules/mdast-util-to-markdown/lib/handle/link.js

/**
 * @import {Info, State} from 'mdast-util-to-markdown'
 * @import {Link, Parents} from 'mdast'
 * @import {Exit} from '../types.js'
 */

import {checkQuote} from '../util/check-quote.js'
import {formatLinkAsAutolink} from '../util/format-link-as-autolink.js'

link.peek = linkPeek

/**
 * @param {Link} node
 * @param {Parents | undefined} _
 * @param {State} state
 * @param {Info} info
 * @returns {string}
 */
export function link(node, _, state, info) {
  const quote = checkQuote(state)
  const suffix = quote === '"' ? 'Quote' : 'Apostrophe'
  const tracker = state.createTracker(info)
  /** @type {Exit} */
  let exit
  /** @type {Exit} */
  let subexit

  if (formatLinkAsAutolink(node, state)) {
    // Hide the fact that we’re in phrasing, because escapes don’t work.
    const stack = state.stack
    state.stack = []
    exit = state.enter('autolink')
    let value = tracker.move('<')
    value += tracker.move(
      state.containerPhrasing(node, {
        before: value,
        after: '>',
        ...tracker.current()
      })
    )
    value += tracker.move('>')
    exit()
    state.stack = stack
    return value
  }

  exit = state.enter('link')
  subexit = state.enter('label')
  let value = tracker.move('[')
  value += tracker.move(
    state.containerPhrasing(node, {
      before: value,
      after: '](',
      ...tracker.current()
    })
  )
  value += tracker.move('](')
  subexit()

  if (
    // If there’s no url but there is a title…
    (!node.url && node.title) ||
    // If there are control characters or whitespace.
    /[\0- \u007F]/.test(node.url)
  ) {
    subexit = state.enter('destinationLiteral')
    value += tracker.move('<')
    value += tracker.move(
      state.safe(node.url, {before: value, after: '>', ...tracker.current()})
    )
    value += tracker.move('>')
  } else {
    // No whitespace, raw is prettier.
    subexit = state.enter('destinationRaw')
    value += tracker.move(
      state.safe(node.url, {
        before: value,
        after: node.title ? ' ' : ')',
        ...tracker.current()
      })
    )
  }

  subexit()

  if (node.title) {
    subexit = state.enter(`title${suffix}`)
    value += tracker.move(' ' + quote)
    value += tracker.move(
      state.safe(node.title, {
        before: value,
        after: quote,
        ...tracker.current()
      })
    )
    value += tracker.move(quote)
    subexit()
  }

  value += tracker.move(')')

  exit()
  return value
}

/**
 * @param {Link} node
 * @param {Parents | undefined} _
 * @param {State} state
 * @returns {string}
 */
function linkPeek(node, _, state) {
  return formatLinkAsAutolink(node, state) ? '<' : '['
}