How to Wait for Asynchronous Callback Functions Simultaneously?

Waiting for Asynchronous Callback Functions Simultaneously

Achieving synchronization of multiple asynchronous callback functions can be challenging. In scenarios where you require the completion of all functions before proceeding, it is crucial to implement a mechanism to wait for their completion.

Manual Counter with Array

A simple approach involves using an array of booleans named "done" to track the callback status. Within each callback function, set done[i] to true to indicate its completion. Create a loop that continuosly checks if all entries in "done" are set to true. Once they are, proceed with the required calculation.

jQuery Promises

jQuery's $.ajax() method returns a promise, which allows you to chain and handle asynchronous operations. Using $.when(), you can create an array of promises and wait for all of them to resolve. When all promises are resolved, the results are available in the callback function arguments.

ES6 Standard Promises

If your environment supports native promises, you can utilize Promise.all(). This method takes an array of promises and returns a single promise that resolves once all input promises have resolved. You can then access the results of each promise within the callback function.

Promisifying Async Operations

If a particular async operation does not return a promise, you can manually create a promise for it. Enclose the async operation within a function and use a resolve() method inside the callback to return the result as a promise.

Bluebird Promises

Bluebird, a popular promise library, extends the functionality of standard promises. Promise.map() allows you to easily map and execute asynchronous operations over an array of data, simplifying the process of waiting for multiple callback functions.

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