code: function link(node, href) {
    var self = this
    var value = 'children' in node ? self.all(node).join('') : node.alt
    var url = escape(typeof href === 'string' ? href : node.url || '')
    var head
  
    if (url && url.slice(0, mailto.length) === mailto) {
      url = url.slice(mailto.length)
    }
  
    head = url.charAt(0) === '#' && self.headings[url.slice(1)]
  
    if (head) {
      url = '(' + escape(toString(head)) + ')'
    } else {
      if (value && escape(url) === value) {
        value = ''
      }
  
      if (url) {
        url = '\\(la' + escape(url) + '\\(ra'
      }
    }
  
    if (value) {
      value = bold.call(self, value)
  
      if (url) {
        value += ' '
      }
    }
  
    return value + (url ? italic.call(self, url) : '')
  }
docs: /* Compile a link.