catchproto.md

Rx.Observable.prototype.catch(second | handler)

Ⓢ

Continues an observable sequence that is terminated by an exception with the next observable sequence. There is an alias for this method catchException for browsers <IE9

Arguments

1. second (Observable): A second observable sequence used to produce results when an error occurred in the first sequence.
2. handler (Function): Exception handler function that returns an observable sequence given the error that occurred in the first sequence

Returns

(Observable): An observable sequence containing the first sequence's elements, followed by the elements of the handler sequence in case an exception occurred.

Example

/* Using a second observable */
var source = Rx.Observable.throw(new Error())
    .catch(Rx.Observable.return(42));

var subscription = source.subscribe(
    function (x) {
        console.log('Next: ' + x.toString());
    },
    function (err) {
        console.log('Error: ' + err);
    },
    function () {
        console.log('Completed');
    });

// => Next: 42
// => Completed

/* Using a handler function */
var source = Rx.Observable.throw(new Error())
    .catch(function (e) {
        return Rx.Observable.return(e instanceof Error);
    });

var subscription = source.subscribe(
    function (x) {
        console.log('Next: ' + x.toString());
    },
    function (err) {
        console.log('Error: ' + err);
    },
    function () {
        console.log('Completed');
    });

// => Next: true
// => Completed

Location

File:

• /src/core/linq/observable/catchproto.js

Dist:

• rx.all.js
• rx.all.compat.js
• rx.js
• rx.compat.js
• rx.lite.js
• rx.lite.compat.js

Prerequisites:

• None

NPM Packages:

• rx

NuGet Packages:

• RxJS-Complete
• RxJS-Main
• RxJS-Lite

Unit Tests:

• /tests/observable/catchexceptionproto.js