How to use the readable-stream/transform.call function in readable-stream

function Stringify(options) {
  if (!(this instanceof Stringify))
    return new Stringify(options || {})
  if (options && options.replacer) {
    this.replacer = options.replacer;
  }
  if (options && options.space !== undefined) {
    this.space = options.space;
  }
  Transform.call(this, options || {})
  this._writableState.objectMode = true

  // Array Deliminator and Stringifier defaults
  var opener = options && options.opener ? options.opener : '[\n'
  var seperator = options && options.seperator ? options.seperator : '\n,\n'
  var closer = options && options.closer ? options.closer : '\n]\n'
  var stringifier = options && options.stringifier ? options.stringifier : stringify

  // Array Deliminators and Stringifier
  this.opener = new Buffer(opener, 'utf8')
  this.seperator = new Buffer(seperator, 'utf8')
  this.closer = new Buffer(closer, 'utf8')
  this.stringifier = stringifier
}

function Parse(opts) {
  var self = this;
  if (!(this instanceof Parse)) {
    return new Parse(opts);
  }

  Transform.call(this, { lowWaterMark: 0 });
  this._opts = opts || { verbose: false };
  this._hasEntryListener = false;

  this._pullStream = new PullStream();
  this._pullStream.on("error", function (e) {
    self.emit('error', e);
  });
  this._pullStream.once("end", function () {
    self._streamEnd = true;
  });
  this._pullStream.once("finish", function () {
    self._streamFinish = true;
  });

  this._readRecord();
}

function ScriptInjectorStream(script, options) {
  var self = this;
  if(!(self instanceof ScriptInjectorStream)) {
    return new ScriptInjectorStream(script, options)
  }

  Transform.call(self, options)

  self._script = script ?
    script+'':
    '('+function() { console.log("You didn't provide a script to inject.") }+')()'
  self.should_inject = true
  self.html_parser = new hp.Parser({
    onprocessinginstruction: function (name, data) {
      self.push('<' + data + '>')
    },
    onopentag: function (name, attribs) {
      var output = ''
      if(name === 'script' && self.should_inject) {
        self.should_inject = false
        output += '

function DestroyableTransform(opts) {
  Transform.call(this, opts)
  this._destroyed = false
}

function DestroyableTransform(opts) {
  Transform.call(this, opts)
  this._destroyed = false
}

function Through2 (override) {
    if (!(this instanceof Through2))
      return new Through2(override)

    this.options = xtend(options, override)

    Transform.call(this, this.options)
  }

function Through2 (override) {
    if (!(this instanceof Through2))
      return new Through2(override)

    this.options = xtend(options, override)

    Transform.call(this, this.options)
  }

function DestroyableTransform(opts) {
  Transform.call(this, opts)
  this._destroyed = false
}

function DestroyableTransform(opts) {
  Transform.call(this, opts)
  this._destroyed = false
}