Use Promise.all

We use Promise or async await to fetch API which is a good approach but it is best for when we have to make a single asynchronous operation, what about if I have to make multiple asynchronous operations like if I have to make fetch for multiple? Here Promise.all() comes into my mind. So, Promise.all() is used for parallel API calling. This means that instead of calling API sequentially, we call API parallel, which speeds up asynchronous operations and reduces time by almost 34%. It is an efficient way to make multiple API calls. How we use Promise.all Promise.all takes promise in array. So to implement this we should follow these steps. create a promising variable whose type should be an array [] first make API calls in the loop or manually without awaiting which means we did not use await. now push each promise into the promise variable. Inside try catch use Promise.all(promise) with async await. const promise = []; for (let i = 0; i < 10; i++) { const getPromise = fetch("https://catfact.ninja/fact", { method: "GET" }); console.log("making promises..."); promise.push(getPromise); } console.log("promise", promise); const resolvePromise = async () => { try { const response = await Promise.all(promise); console.log("response", response); } catch (error) { console.log("error", error); } }; resolvePromise();

Mar 18, 2025 - 19:41

We use Promise or async await to fetch API which is a good approach but it is best for when we have to make a single asynchronous operation, what about if I have to make multiple asynchronous operations like if I have to make fetch for multiple? Here Promise.all() comes into my mind.
So, Promise.all() is used for parallel API calling. This means that instead of calling API sequentially, we call API parallel, which speeds up asynchronous operations and reduces time by almost 34%. It is an efficient way to make multiple API calls.

How we use Promise.all
Promise.all takes promise in array.
So to implement this we should follow these steps.

create a promising variable whose type should be an array []
first make API calls in the loop or manually without awaiting which means we did not use await.
now push each promise into the promise variable.
Inside try catch use Promise.all(promise) with async await.

const promise = [];

for (let i = 0; i < 10; i++) {
  const getPromise = fetch("https://catfact.ninja/fact", { method: "GET" });
  console.log("making promises...");
  promise.push(getPromise);
}
console.log("promise", promise);
const resolvePromise = async () => {
  try {
    const response = await Promise.all(promise);
    console.log("response", response);
  } catch (error) {
    console.log("error", error);
  }
};

resolvePromise();