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Promise.prototype.catch()

Method catch() mengembalikan Promise dan hanya setuju jika kasusnya gagal. Sama halnya dengan memenggil method Promise.prototype.then(undefined, onRejected).

Sintaks

p.catch(onRejected);

p.catch(function(reason) {
   // rejection
});

Parameter

onRejected
 Function dipanggil ketika Promise ditolak. Fungsi ini memiliki satu argumen, alasan penolakan.

Deskripsi

Method catch sangat berguna untuk menangani error di gabungan promis anda.

Contoh

Penggunaan method catch

var p1 = new Promise(function(resolve, reject) {
  resolve('Success');
});

p1.then(function(value) {
  console.log(value); // "Success!"
  throw 'oh, no!';
}).catch(function(e) {
  console.log(e); // "oh, no!"
}).then(function(){
  console.log('after a catch the chain is restored');
}, function () {
  console.log('Not fired due to the catch');
});

// The following behaves the same as above
p1.then(function(value) {
  console.log(value); // "Success!"
  return Promise.reject('oh, no!');
}).catch(function(e) {
  console.log(e); // "oh, no!"
}).then(function(){
  console.log('after a catch the chain is restored');
}, function () {
  console.log('Not fired due to the catch');
});

Promis tidak dapat mendeteksi error pada asynchronous callback

var p1 = new Promise(function(resolve, reject) {
  throw 'Uh-oh!';
});

p1.catch(function(e) {
  console.log(e); // "Uh-oh!"
});


var p2 = new Promise(function(resolve, reject) {
  setTimeout(function() {
    throw 'Uncaught Exception!';
  }, 1000);
});

p2.catch(function(e) {
  console.log(e); // This is never called
});

Spesifikasi

Spesifikasi Status Comment
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Promise.prototype.catch' in that specification.
Standard Initial definition in an ECMA standard.
ECMAScript 2017 Draft (ECMA-262)
The definition of 'Promise.prototype.catch' in that specification.
Draft  

Kompabilitas Browser

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support 32 29.0 (29.0) No support 19 7.1
Feature Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile Chrome for Android
Basic support No support 29.0 (29.0) No support No support 8 32

Lihat Juga

Tag Dokumen dan Kontributor

 Kontributor untuk laman ini: rmsubekti
 Terakhir diperbarui oleh: rmsubekti,