indexeddb-promises/example-tx-wait.html at master · inexorabletash/indexeddb-promises · GitHub

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<!DOCTYPE html>
<title>IDBTransaction.waitUntil()</title>
<script src="polyfill.js"></script>
<script>
'use strict';

function sleep(ms) {
  return new Promise(function(resolve) {
    setTimeout(resolve, ms);
  });
}

var open = indexedDB.open('db' + Date.now());
open.onupgradeneeded = function() {
  var db = open.result;
  var s = db.createObjectStore('squares');
  for (var i = 0; i < 10; ++i) {
    s.put(i * i, i);
  }
};

open.onsuccess = function() {
  var db = open.result;
  console.log('-- creating tx --');
  var tx = db.transaction('squares');
  var s = tx.objectStore('squares');
  console.log('state >> ' + tx.state);

  (function() {
    console.assert(tx.complete === tx.complete);

    var rq = s.get(0);
    console.assert(rq.ready === rq.ready);
  }());

  var rq, rq2, p2;
  tx.waitUntil(
    rq = s.get(3).ready
     .then(function(result) {
       console.log('tx state >> ' + tx.state);
       console.log('result >> ' + result);
       return sleep(10);
     })
     .then(function() {
       console.log('tx state >> ' + tx.state);
       rq2 = s.get(5);
       p2 = rq2.ready;
       return p2;
     })
     .then(function(result) {
       console.assert(p2 === rq2.ready);
       console.log('tx state >> ' + tx.state);
       console.log('result >> ' + result);
       return sleep(10);
     })
  ).then(function() {
    console.log('tx then, state >> ' + tx.state);
  }, function() {
    console.log('tx caught, state >> ' + tx.state);
  });
};

</script>