The catch() method returns a Promise and deals with rejected cases only. It behaves the same as calling Promise.prototype.then(undefined, onRejected).
Syntax
p.catch(onRejected);
p.catch(function(reason) {
// rejection
});
Parameters
- onRejected
- A
Functioncalled when thePromiseis rejected. This function has one argument, the rejectionreason.
Description
The catch method can be useful for error handling in your promise composition.
Examples
Using the catch method
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');
});
Specifications
| Specification | 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 |
Browser compatibility
| 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 |
