One possible implementation could be:

function all(promises) {
  // write your code here

  // to store results
  const results = [];

  //to track how many promises have been completed
  let completedPromises = 0;

  function handler(resolve, reject) {
    for (let i = 0; i &lt; promises.length; i++) {
      const promise = promises[i];
      
      promise
        .then((result) =&gt; {
          results[i] = result;
          completedPromises += 1;

          if (completedPromises === promises.length) {
            resolve(results);
            return;
          }
        })
        .catch((error) =&gt; {
          reject(error);
        });
    }
  }
  
  return new Promise(handler);
}

Promise.all = all;

Read more about Promise.all() here:

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/all

How to implement Promise.all? | Promise Polyfills | Advanced JavaScript Interview Question

@Yomesh Gupta