The Promise.prototype property represents the prototype for the Promise constructor.

Property attributes of Promise.prototype
Writable no
Enumerable no
Configurable no

Description

Promise instances inherit from Promise.prototype. You can use the constructor's prototype object to add properties or methods to all Promise instances.

Properties

Promise.prototype.constructor
Returns the function that created an instance's prototype. This is the Promise function by default.

Methods

Promise.prototype.catch(onRejected)
Appends a rejection handler callback to the promise, and returns a new promise resolving to the return value of the callback if it is called, or to its original fulfillment value if the promise is instead fulfilled.
Promise.prototype.then(onFulfilled, onRejected)
Appends fulfillment and rejection handlers to the promise, and returns a new promise resolving to the return value of the called handler, or to its original settled value if the promise was not handled (i.e. if the relevant handler onFulfilled or onRejected is not a function).
Promise.prototype.finally(onFinally)
Appends a handler to the promise, and returns a new promise which is resolved when the original promise is resolved. The handler is called when the promise is settled, whether fulfilled or rejected.

Specifications

Specification Status Comment
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Promise.prototype' in that specification.
Standard Initial definition.
ECMAScript Latest Draft (ECMA-262)
The definition of 'Promise.prototype' in that specification.
Draft  

Browser compatibility

Update compatibility data on GitHub
DesktopMobileServer
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidiOS SafariSamsung InternetNode.js
Basic supportChrome Full support 32Edge Full support YesFirefox Full support 29IE No support NoOpera Full support 19Safari Full support 8WebView Android Full support 4.4.3Chrome Android Full support 32Edge Mobile Full support YesFirefox Android Full support 29Opera Android Full support YesSafari iOS Full support 8Samsung Internet Android Full support Yesnodejs Full support 0.12

Legend

Full support  
Full support
No support  
No support

See also

Document Tags and Contributors

Contributors to this page: jsx, fscholz, tarungarg546, bitzstein, realityking
Last updated by: jsx,