How To Stop Javascript Execution Until Event

In this blog post, we will explore how to stop the execution of JavaScript code until a specific event occurs. This can be particularly useful in situations where you need to wait for a user action, such as a button click or an API response, before proceeding with the rest of your code.

Using Promises and Async/Await

One way to achieve this is by using Promises and the async/await syntax. A Promise is an object that represents the eventual completion (or failure) of an asynchronous operation and its resulting value. The async/await syntax allows us to work with Promises in a more concise and readable manner.

function waitForEvent(eventName) {
  return new Promise((resolve) => {
    document.addEventListener(eventName, () => {
      resolve();
    }, { once: true });
  });
}

async function executeCodeAfterEvent() {
  console.log('Waiting for the event to occur...');
  await waitForEvent('myCustomEvent');
  console.log('The event has occurred! Proceeding with code execution...');
}

executeCodeAfterEvent();

In the code snippet above, we define a function called waitForEvent that takes an event name as its parameter and returns a Promise. The Promise is resolved when the specified event occurs. We also define an async function called executeCodeAfterEvent that calls waitForEvent and waits for the Promise to resolve before proceeding with the rest of the code.

Using Callback Functions

Another approach to stop JavaScript execution until an event occurs is by using callback functions. A callback function is a function that is passed as an argument to another function and is executed when a particular event occurs. In this approach, you can define your event listener and pass your callback function as an argument.

function waitForEvent(eventName, callback) {
  document.addEventListener(eventName, () => {
    callback();
  }, { once: true });
}

function executeCodeAfterEvent() {
  console.log('Waiting for the event to occur...');
  waitForEvent('myCustomEvent', () => {
    console.log('The event has occurred! Proceeding with code execution...');
  });
}

executeCodeAfterEvent();

In the code snippet above, we define a function called waitForEvent that takes an event name and a callback function as its parameters. When the specified event occurs, the callback function is executed. We then define a function called executeCodeAfterEvent that calls waitForEvent and passes a callback function to be executed when the event occurs.

Conclusion

In this blog post, we have explored two different approaches to stop JavaScript execution until a specific event occurs. By using Promises and async/await or callback functions, you can easily manage the flow of your code based on user actions or other events.