WorkerGlobalScope: fetch() method
Baseline
Widely available
*
This feature is well established and works across many devices and browser versions. It’s been available across browsers since March 2017.
* Some parts of this feature may have varying levels of support.
Note: This feature is only available in Web Workers.
The fetch() method of the WorkerGlobalScope interface starts the process of fetching a resource from the network, returning a promise that is fulfilled once the response is available.
The promise resolves to the Response object representing the response to your request.
A fetch() promise only rejects when the request fails, for example, because of a badly-formed request URL or a network error.
A fetch() promise does not reject if the server responds with HTTP status codes that indicate errors (404, 504, etc.).
Instead, a then() handler must check the Response.ok and/or Response.status properties.
The fetch() method is controlled by the connect-src directive of Content Security Policy rather than the directive of the resources it's retrieving.
Note:
The fetch() method's parameters are identical to those of the Request() constructor.
Syntax
js
fetch(resource)
fetch(resource, options)
Parameters
resource-
This defines the resource that you wish to fetch. This can either be:
- A string or any other object with a stringifier — including a
URLobject — that provides the URL of the resource you want to fetch. The URL may be relative to the base URL, which is the document'sbaseURIin a window context, orWorkerGlobalScope.locationin a worker context. - A
Requestobject.
- A string or any other object with a stringifier — including a
optionsOptional-
A
RequestInitobject containing any custom settings that you want to apply to the request.
Return value
Exceptions
AbortErrorDOMException-
The request was aborted due to a call to the
AbortControllerabort()method. NotAllowedErrorDOMException-
Thrown if use of the Topics API is specifically disallowed by a
browsing-topicsPermissions Policy, and afetch()request was made withbrowsingTopics: true. TypeError-
An error when the fetch operation could not be performed. See
Window.fetch()exceptions for a list of reasons why this error can occur.
Examples
See fetch() for examples.
Specifications
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| Fetch # fetch-method |
Browser compatibility
| desktop | mobile | server | |||||||||||||
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fetch
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Authorization header removed from cross-origin redirects
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Support for blob: and data:
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options parameter
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attributionReporting property
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body property
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ReadableStream body
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browsingTopics property
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duplex property
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keepalive property
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priority property
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privateToken property
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referrerPolicy property
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signal property
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targetAddressSpace property
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Legend
Tip: you can click/tap on a cell for more information.
- Full support
- Full support
- No support
- No support
- Experimental. Expect behavior to change in the future.
- Non-standard. Check cross-browser support before using.
- Deprecated. Not for use in new websites.
- See implementation notes.
- Has more compatibility info.