How to Make a Wait Function in JavaScript
In JavaScript, there are various scenarios where you might need to pause the execution of a function for a certain period of time. This is particularly useful when you want to create a delay between tasks or when you want to synchronize the execution of different functions. One way to achieve this is by creating a custom wait function. In this article, we will discuss how to make a wait function in JavaScript and explore different methods to implement it.
One of the simplest ways to create a wait function in JavaScript is by using the `setTimeout` function. The `setTimeout` function allows you to delay the execution of a function by a specified number of milliseconds. Here’s an example of how you can create a wait function using `setTimeout`:
“`javascript
function wait(duration) {
return new Promise(resolve => {
setTimeout(resolve, duration);
});
}
“`
In this example, the `wait` function takes a `duration` parameter, which represents the number of milliseconds to wait before resolving the promise. Inside the function, we create a new promise and pass a callback function to the `setTimeout` function. The callback function is called once the specified duration has elapsed, and it resolves the promise.
You can use this `wait` function in your code like this:
“`javascript
async function performTask() {
console.log(‘Starting task…’);
await wait(2000); // Wait for 2 seconds
console.log(‘Task completed!’);
}
performTask();
“`
In the above example, the `performTask` function is an asynchronous function that logs “Starting task…” and then waits for 2 seconds using the `wait` function. After the delay, it logs “Task completed!”.
Another way to create a wait function in JavaScript is by using the `Promise.race` function along with `setTimeout`. This method is useful when you want to cancel the wait function if a certain condition is met before the specified duration has elapsed. Here’s an example:
“`javascript
function wait(duration, cancelCondition) {
return new Promise((resolve, reject) => {
const timeoutId = setTimeout(() => {
resolve();
}, duration);
if (cancelCondition()) {
clearTimeout(timeoutId);
reject(new Error(‘Wait function was cancelled.’));
}
});
}
“`
In this example, the `wait` function takes two parameters: `duration` and `cancelCondition`. The `duration` parameter represents the number of milliseconds to wait, and the `cancelCondition` is a function that returns a boolean value indicating whether the wait function should be cancelled.
You can use this `wait` function in your code like this:
“`javascript
async function performTask() {
console.log(‘Starting task…’);
try {
await wait(2000, () => true); // Wait for 2 seconds, but cancel if the condition is met
} catch (error) {
console.error(error.message);
}
console.log(‘Task completed!’);
}
performTask();
“`
In the above example, the `performTask` function attempts to wait for 2 seconds using the `wait` function. However, if the `cancelCondition` function returns `true`, the wait function will be cancelled, and an error will be thrown.
In conclusion, creating a wait function in JavaScript can be achieved using different methods, such as `setTimeout` or `Promise.race`. These methods provide flexibility and control over the execution of your code, allowing you to create delays and synchronize tasks effectively.
