DavidV

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• Simple Promise Example

  @DavidV started

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  @allObjects replied
• Simple Promise Example

  in Tutorials • 4 years, 5 months

  

  This is a super simple example of using promises to order execution of functions asyncronously.

  // Simple promise
  function Kvp(key, value) {
    return new Promise(function(resolve, reject) {
      console.log(key, value);
      resolve();
    });
  }
  
  // Promise which runs every value second
  function RunOn(value) {
    return new Promise(function(resolve, reject) {
      setInterval(function() {
        console.log(new Date().toISOString().substring(11, 19));
        resolve();
      }, value * 1000);
    });
  }
  
  // Promise which runs once after value seconds
  function RunOnce(value) {
    return new Promise(function(resolve, reject) {
      var runOnce = setInterval(() => {
        console.log("RunOnce", value);
        clearInterval(runOnce); //stop function
        resolve();
      }, value * 1000);
    });
  }
  
  RunOn(1);
  Kvp('A', 1).then(function() {
    Kvp('B', 2);
  });
  RunOnce(5).then(() => {
    Kvp("C", 5);
  }).then(() => {
    Kvp('fin', 12);
  });