promise.html - A JavaScript Promise Example.

promise.html

<script>
/* cf. https://developer.mozilla.org/ja/docs/Web/JavaScript/Reference/Global_Objects/Promise */
'use strict';

var promiseCount = 0;

function runPromise() {
  let id = promiseCount++;
  console.log("runPromise: START: " + id);

  new Promise(
    (resolve, reject) => {
      console.log("runPromise: EXEC: " + id);
      window.setTimeout(
        function() {
          if (Math.random() > 0.5) {
            resolve(id);
          } else {
            reject(id);
          }
        },
        Math.random() * 6000 
      );
    }
  ).then(
    (arg) => {
      console.log("RESOLVED: " + arg);
    }
  ).catch(
    (arg) => {
      console.log("REJECTED: " + arg);
    }
  );

  console.log("runPromise: END: " + id);
}

console.log("START");
window.setInterval(runPromise, 3000);

</script>