How to Execute Promises Sequentially with Parameters from a Dynamically Populated Array?

Promises Chaining: Executing Promises Sequentially with Parameters from an Array

In asynchronous programming, promises offer a robust mechanism for handling asynchronous operations. In this scenario, you seek to execute a promise function sequentially for each element within an array, while ensuring that each promise resolves before moving on to the next.

Dynamically Populating Arrays and Promise Execution

Your goal is to dynamically populate an array with data and execute a promise function for each item in the array. However, the current approach through .then() chaining in a loop has limitations when the array is dynamically populated. To address this, we present two optimal solutions:

Fold Expressions:

1. Create an array of promises with myArray.reduce().
2. Resolve the array of promises in a sequential order using Promise.resolve().

This approach effectively maps each item in the array to its promise and executes them in sequence. However, it can lead to high memory overhead if the array size is significant.

Async Functions:

1. Utilize an async function forEachSeries().
2. Iterate through the array and await the resolution of each promise using await action(x).

Async functions offer the advantage of conciseness, readability, and optimal memory usage (O(1)). Additionally, you can extend this approach to collect return values.

Snippet:

<code class="javascript">const forEachSeries = async (iterable, action) => {
  for (const x of iterable) {
    await action(x);
  }
};

forEachSeries(myArray, myPromise).then(() => {
  console.log('all done!');
});</code>

This updated snippet resolves your requirement for executing promises sequentially from a dynamically populated array, ensuring that each promise resolves before proceeding to the next.

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