AI solution for JavaScript Coding Question on BFE.dev
34. implement `Promise.any()`

Here's one possible implementation of Promise.any():

class AggregateError extends Error {
  constructor(message, errors) {
    super(message);
    this.name = 'AggregateError';
    this.errors = errors;
  }
}

Promise.any = function(promises) {
  return new Promise((resolve, reject) => {
    const errors = [];
    let resolved = false;

    for (const promise of promises) {
      promise.then(
        value => {
          if (!resolved) {
            resolved = true;
            resolve(value);
          }
        },
        error => {
          errors.push(error);
          if (errors.length === promises.length) {
            reject(new AggregateError('No Promise in Promise.any was resolved', errors));
          } 
        }
      );
    }
  });
};

// Example usage:
const promise1 = new Promise(resolve => setTimeout(() => resolve('hello'), 100));
const promise2 = new Promise((_, reject) => setTimeout(() => reject(new Error('error')), 200));
const promise3 = new Promise(resolve => setTimeout(() => resolve('world'), 300));

Promise.any([promise1, promise2, promise3])
  .then(console.log) // outputs "hello"
  .catch(console.error); // will not be called 

The implementation creates a new Promise and loops through the input promises, adding then and catch handlers to each one. When a promise fulfills, the then handler checks if a promise has already been resolved; if not, it resolves the new promise with the value from that promise. When a promise is rejected, the catch handler adds the error to an array of errors, and checks if all promises have been rejected; if so, it rejects the new promise with an AggregateError.