catchproto.md

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

Ⓢ

Continues an observable sequence that is terminated by an exception with the next observable sequence.

Arguments

Using another Observable:

• second (Observable): A second observable sequence used to produce results when an error occurred in the first sequence.

Using a handler:

• 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.just(42));

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

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

/* Using a handler function */
var source = Rx.Observable.throw(new TimeoutError())
    .catch(function (e) {
      var returnValue;
      if (e instanceof TimeoutError) { return Rx.Observable.just(42); }
      return Rx.Observable.throw(e);
    });

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

// => Next: 42
// => 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