javascript - es2016处理类构造函数中的回调[重复](es2016 handling callbacks in class constructor [duplicate])

Question

(This question already has answers here) : ((这个问题已经在这里有了答案) ：)

Is it bad practice to have a constructor function return a Promise? (让构造函数返回Promise是不好的做法吗？) (4 answers) (（4个答案）)

Closed 7 hours ago . (7小时前关闭。)

I'm trying to write the following code into a es2015 class syntax:(我正在尝试将以下代码编写为es2015类语法：)

export function initialize(port) { return new Promise((resolve, reject) => { const application = express(); const server = application.listen(port, function listening(error) { if (error) reject(error); resolve(server); }); }); } const server = async initialize(port); es2015:(es2015：) class Server { constructor(port) { return new Promise((resolve, reject) => { const application = express(); const server = application.listen(port, function listening(error) { if (error) reject(error); resolve(server); }); }); } } const server = async new Server(port); // <-- not a good idea! Apparently returning and a Promise is not such a good idea when using the new which should return an instant instance.(显然，使用new的Promise返回一个即时实例并不是一个好主意。) Any ideas?(有任何想法吗？)   ask by Karl Morrison translate from so

Answer 1

You could use a separate initialise method and call that from instance:(您可以使用单独的initialise方法，并从实例调用该方法：)

class Server { constructor(port) { this.port = port; } initialise() { return new Promise((resolve, reject) => { const application = express(); const server = application.listen(this.port, function listening(error) { if (error) reject(error); resolve(server); }); }); } } const server = new Server(port); server.initialise().then(() => // do some stuff)