Cached Promises

cached-promises.js

// Thanks to
// https://github.com/microsoft/tsyringe/issues/66#issuecomment-566755746
// https://262.ecma-international.org/6.0/#sec-promise-resolve-functions

main();

async function main() {
  const rnd = getRandom();
  console.log(await rnd);
  console.log(await rnd);
  console.log(await rnd);
}

async function getRandom() {
  return Promise.resolve(Math.random());
}

// Outputs
// 0.2904893310271659
// 0.2904893310271659
// 0.2904893310271659