聆听JavaScript中事件的缺失

Question

第三方JS插件发出一个可以监听的事件：

jsInt.on('ready', function(services) {
    if(Array.isArray(services) && ~services.indexOf('magic')) {
        //integration is ready to use and it has 'magic' service available
    } else {
        //integration is ready to use but it does not have 'magic' service
    }
});

如何以编程方式检测3秒钟内是否没有发生此事件？

Answer 1

让on回调取消一个超时，该超时在3秒后运行：

const timeoutId = setTimeout(() => {
  console.log('Library did not load in time!');
  // ...handle the problem
}, 3000);

jsInt.on('ready', function(services) {
  clearTimeout(timeoutId);

  // rest of the code
  if(Array.isArray(services) && ~services.indexOf('magic')) {
    //integration is ready to use and it has 'magic' service available
  } else {
    //integration is ready to use but it does not have 'magic' service
  }
});

Answer 2

这就是诺言。

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