Add support for setting responseType of xhr via m.request options

docs/change-log.md

@@ -35,6 +35,7 @@
 - API: `m.route.link` accepts an optional `options` object ([#1930](https://github.com/MithrilJS/mithril.js/pull/1930))
 - API: `m.request` better error message on JSON parse error - ([#2195](https://github.com/MithrilJS/mithril.js/pull/2195), [@codeclown](https://github.com/codeclown))
 - API: `m.request` supports `timeout` as attr - ([#1966](https://github.com/MithrilJS/mithril.js/pull/1966))
+- API: `m.request` supports `responseType` as attr - ([#2193](https://github.com/MithrilJS/mithril.js/pull/2193))
 - Mocks: add limited support for the DOMParser API ([#2097](https://github.com/MithrilJS/mithril.js/pull/2097))
 - API: add support for raw SVG in `m.trust()` string ([#2097](https://github.com/MithrilJS/mithril.js/pull/2097))
 - render/core: remove the DOM nodes recycling pool ([#2122](https://github.com/MithrilJS/mithril.js/pull/2122))

docs/request.md

@@ -50,6 +50,7 @@ Argument                  | Type                              | Required | Descr
 `options.password`        | `String`                          | No       | A password for HTTP authorization. Defaults to `undefined`. This option is provided for `XMLHttpRequest` compatibility, but you should avoid using it because it sends the password in plain text over the network.
 `options.withCredentials` | `Boolean`                         | No       | Whether to send cookies to 3rd party domains. Defaults to `false`
 `options.timeout`         | `Number`                          | No       | The amount of milliseconds a request can take before automatically being [terminated](https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/timeout).  Defaults to `undefined`.
+`options.responseType`    | `String`                          | No       | The expected [type](https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/responseType) of the response. Defaults to `undefined`.
 `options.config`          | `xhr = Function(xhr)`             | No       | Exposes the underlying XMLHttpRequest object for low-level configuration. Defaults to the [identity function](https://en.wikipedia.org/wiki/Identity_function).
 `options.headers`         | `Object`                          | No       | Headers to append to the request before sending it (applied right before `options.config`).
 `options.type`            | `any = Function(any)`             | No       | A constructor to be applied to each object in the response. Defaults to the [identity function](https://en.wikipedia.org/wiki/Identity_function).

request/request.js

@@ -76,6 +76,8 @@ module.exports = function($window, Promise) {
 			if (args.withCredentials) xhr.withCredentials = args.withCredentials
 
 			if (args.timeout) xhr.timeout = args.timeout
+			
+			if (args.responseType) xhr.responseType = args.responseType
 
 			for (var key in args.headers) if ({}.hasOwnProperty.call(args.headers, key)) {
 				xhr.setRequestHeader(key, args.headers[key])

request/tests/test-request.js

@@ -449,6 +449,20 @@ o.spec("xhr", function() {
 				}
 			})
 		})
+		o("set responseType to xhr instance", function() {
+			mock.$defineRoutes({
+				"GET /item": function() {
+					return {status: 200, responseText: ""}
+				}
+			})
+			return xhr({
+				method: "GET", url: "/item",
+				responseType: "blob",
+				config: function(xhr) {
+					o(xhr.responseType).equals("blob")
+				}
+			})
+		})
 		/*o("data maintains after interpolate", function() {
 			mock.$defineRoutes({
 				"PUT /items/:x": function() {