Response: json() static method
The json()
static method of the Response
interface returns a Response
that contains the provided JSON data as body, and a Content-Type
header which is set to application/json
.
The response status, status message, and additional headers can also be set.
The method makes it easy to create Response
objects for returning JSON encoded data.
Service workers, for example, intercept fetch requests made by a browser, and might use json()
to construct a Response
from cached JSON data to return to the main thread.
The json()
method can also be used in server code to return JSON data for single page applications, and any other applications where a JSON response is expected.
Syntax
js
Response.json(data)
Response.json(data, options)
Parameters
data
-
The JSON data to be used as the response body.
options
Optional-
An options object containing settings for the response, including the status code, status text, and headers. This is the same as the options parameter of the
Response()
constructor.status
-
The status code for the response, such as
200
. statusText
-
The status message associated with the status code. For a status of
200
this might beOK
. headers
-
Any headers you want to add to your response, contained within a
Headers
object or object literal ofString
key/value pairs (see HTTP headers for a reference).
Return value
A Response
object.
Exceptions
TypeError
-
Thrown if
data
cannot be converted to a JSON string. This might happen if the data is a JavaScript object that has method, or that has a circular reference, or if the passed object isundefined
.
Examples
Response with JSON data
This live example shows how you can create a JSON response object, and logs the newly created object for inspection (the logging code is hidden as it is not relevant).
The code below creates a Response
object with JSON body { my: "data" }
and header set to application/json
.
js
const jsonResponse = Response.json({ my: "data" });
logResponse(jsonResponse);
The object has the following properties.
Note the body and header are set as expected, and that the default status is set to 200
.
Response with JSON data and options
This example shows how you can create a JSON response object with status
and statusText
options.
The code below creates a Response
object with JSON body { some: "data", more: "information" }
and header set to application/json
.
It also sets the status to 307
and sets the appropriate status text ("Temporary Redirect").
js
const jsonResponse = Response.json(
{ some: "data", more: "information" },
{ status: 307, statusText: "Temporary Redirect" }
);
logResponse(jsonResponse);
The object has the following properties, which are set as expected.
Note that the ok
property of the response changed to false
as the status value is not in the range of 200 to 299.
Specifications
Specification |
---|
Fetch Standard # ref-for-dom-response-json① |
Browser compatibility
BCD tables only load in the browser