.then example javascript

Example 1: promise catch

//create a Promise
var p1 = new Promise(function(resolve, reject) {
  resolve("Success");
});

//Execute the body of the promise which call resolve
//So it execute then, inside then there's a throw
//that get capture by catch
p1.then(function(value) {
  console.log(value); // "Success!"
  throw "oh, no!";
}).catch(function(e) {
  console.log(e); // "oh, no!"
});

Example 2: promise chaining

new Promise(function(resolve, reject) {

  setTimeout(() => resolve(1), 1000); // (*)

}).then(function(result) { // (**)

  alert(result); // 1
  return result * 2;

}).then(function(result) { // (***)

  alert(result); // 2
  return result * 2;

}).then(function(result) {

  alert(result); // 4
  return result * 2;

});

Example 3: .then javascript

const promise2 = doSomething().then(successCallback, failureCallback);

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Misc Example

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