Abort previous pending XHR when navigating

tests/lib/abort-request.js

@@ -0,0 +1,54 @@
+var tape = require("tape")
+
+var abortRequest = require("../../lib/abort-request.js")
+var sendRequest = require("../../lib/send-request.js")
+
+// Polyfill responseURL property into XMLHttpRequest if it doesn't exist,
+// just for the purposes of this test
+// This polyfill is not complete; it won't show the updated location if a
+// redirection occurred, but it's fine for our purposes.
+if (!("responseURL" in XMLHttpRequest.prototype)) {
+  var nativeOpen = XMLHttpRequest.prototype.open
+  XMLHttpRequest.prototype.open = function(method, url) {
+    this.responseURL = url
+    return nativeOpen.apply(this, arguments)
+  }
+}
+
+tape("test aborting xhr request", function(t) {
+  var requestCacheBust = sendRequest.bind({
+    options: {
+      cacheBust: true,
+    },
+  })
+
+  t.test("- pending request is aborted", function(t) {
+    var r = requestCacheBust("https://httpbin.org/delay/10", {}, function() {})
+    t.equal(r.readyState, 1, "xhr readyState is '1' (SENT)")
+    abortRequest(r)
+    t.equal(r.readyState, 0, "xhr readyState is '0' (ABORTED)")
+    t.equal(r.status, 0, "xhr HTTP status is '0' (ABORTED)")
+    t.equal(r.responseText, "", "xhr response is empty")
+    t.end()
+  })
+  t.test("- request is not aborted if it has already completed", function(t) {
+    var r = requestCacheBust("https://httpbin.org/get", {}, function() {
+      abortRequest(r)
+      t.equal(r.readyState, 4, "xhr readyState is '4' (DONE)")
+      t.equal(r.status, 200, "xhr HTTP status is '200' (OK)")
+      t.end()
+    })
+  })
+  t.test("- request is not aborted if it is undefined", function(t) {
+    var r
+    try {
+      abortRequest(r)
+    }
+    catch (e) {
+      t.fail("aborting an undefined request threw an error")
+    }
+    t.equal(typeof r, "undefined", "undefined xhr was ignored")
+    t.end()
+  })
+  t.end()
+})