Merge pull request #333 from barneycarroll/propSafeRequest

`initialValue` property for `m.request`, with tests

mithril.js

@@ -949,6 +949,7 @@ Mithril = m = new function app(window, undefined) {
 			if (xhrOptions.background !== true) m.endComputation()
 		}
 		ajax(xhrOptions)
+		deferred.promise(xhrOptions.initialValue)
 		return deferred.promise
 	}
 

tests/mithril-tests.js

@@ -1687,6 +1687,18 @@ function testMithril(mock) {
 		xhr.onreadystatechange()
 		return xhr.$headers["Content-Type"] === undefined
 	})
+	test(function() {
+		var prop = m.request({method: "POST", url: "test", initialValue: "foo"})
+		var initialValue = prop();
+		mock.XMLHttpRequest.$instances.pop().onreadystatechange()
+
+		return initialValue === "foo"
+	})
+	test(function() {
+		var prop = m.request({method: "POST", url: "test", initialValue: "foo"}).then(function(value) {return "bar"})
+		mock.XMLHttpRequest.$instances.pop().onreadystatechange()
+		return prop() === "bar"
+	})
 
 	// m.request over jsonp
 	test(function(){