List the static methods of Promise and explain what a promise is.

Promise is an object in JavaScript that represents the result of an asynchronous operation and can be in one of three states: pending, fulfilled, or rejected. It allows for more convenient handling of asynchronous code, avoiding "callback hell".

Static methods of Promise:

• Promise.resolve(value) — creates a promise that is immediately fulfilled with the given value.
• Promise.reject(reason) — creates a promise that is immediately rejected with the given reason.
• Promise.all(iterable) — returns a promise that fulfills when all promises in the iterable are fulfilled, or rejects if any promise is rejected.
• Promise.race(iterable) — returns a promise that fulfills or rejects as soon as the first promise in the iterable fulfills or rejects.
• Promise.allSettled(iterable) — returns a promise that fulfills when all promises in the iterable have settled (fulfilled or rejected), with an array of results.
• Promise.any(iterable) — returns a promise that fulfills as soon as any promise in the iterable fulfills, or rejects if all are rejected.

Example usage:

Promise.all([fetch(url1), fetch(url2)])
  .then(([res1, res2]) => {
    // handle results
  })
  .catch(error => {
    // handle error
  });