isTrusted(e) {
    if (e.url && !e.protocol) {
      var t = re.protocolFromUrl(e.url);
      if (t == null)
        return !1;
      e.protocol = t;
    }
    var r = typeof this.trust == "function" ? this.trust(e) : this.trust;
    return !!r;
  }
Check whether to test potentially dangerous input, and return
`true` (trusted) or `false` (untrusted).  The sole argument `context`
should be an object with `command` field specifying the relevant LaTeX
command (as a string starting with `\`), and any other arguments, etc.
If `context` has a `url` field, a `protocol` field will automatically
get added by this function (changing the specified object).