javascript - 如何在“then()”函数中更新和调用

Question

playSpeech(body) {
    this._isSpeaking = true;

    this._hostSpeechComponent.addSpeech(this._speech);

    this._speech.updateConfig({
        entity: this._host,
        body: '<speak>' + body + '</speak>',
        type: 'ssml',
        voice: this._voice
    });

    this._speech.play().then(() => {
        this._isSpeaking = false;
    });
};

这是我在 Amazon Sumerian Script 中的 PlaySpeech 方法。在“then”函数中，我想更新speech.body，然后调用speech.play()。我该怎么做？