相关疑难解决方法(0)

我正在使用Firebase开发Server.

我在Youtube上复制了Google Developer's Video .

它运行良好,但在日志中有一个错误:

函数返回undefined,预期Promise或value

它说函数返回了undefined,但是我function返回一个promise`set``

我怎么解决这个问题？

function sanitize(s) {
    var sanitizedText = s;
    console.log('sanitize params: ', sanitizedText);
    sanitizedText = sanitizedText.replace(/\bstupid\b/ig, "wonderful");
    return sanitizedText;
}
exports.sanitizePost = functions.database
    .ref('/posts/{pushId}')
    .onWrite(event => {
        const post = event.data.val();
        if (post.sanitized) return;

        console.log('Sanitizing new post', event.params.pushId);
        console.log(post);
        post.sanitized = true;
        post.title = sanitize(post.title);
        post.body = sanitize(post.body);
        return event.data.ref.set(post); 
    })

我是Firebase,Nodejs的初学者.