Actually add in the setImmediate module.

src/generic/setImmediate.ts

@@ -0,0 +1,65 @@
+import global from '../core/global';
+
+let bfsSetImmediate: (cb: Function) => any;
+if (typeof(setImmediate) !== "undefined") {
+  bfsSetImmediate = setImmediate;
+} else {
+  const gScope = global;
+  const timeouts: (() => void)[] = [];
+  const messageName = "zero-timeout-message";
+  const canUsePostMessage = function() {
+    if (typeof gScope.importScripts !== 'undefined' || !gScope.postMessage) {
+      return false;
+    }
+    let postMessageIsAsync = true;
+    const oldOnMessage = gScope.onmessage;
+    gScope.onmessage = function() {
+      postMessageIsAsync = false;
+    };
+    gScope.postMessage('', '*');
+    gScope.onmessage = oldOnMessage;
+    return postMessageIsAsync;
+  };
+  if (canUsePostMessage()) {
+    bfsSetImmediate = function(fn: () => void) {
+      timeouts.push(fn);
+      gScope.postMessage(messageName, "*");
+    };
+    const handleMessage = function(event: MessageEvent) {
+      if (event.source === self && event.data === messageName) {
+        if (event.stopPropagation) {
+          event.stopPropagation();
+        } else {
+          event.cancelBubble = true;
+        }
+        if (timeouts.length > 0) {
+          const fn = timeouts.shift()!;
+          return fn();
+        }
+      }
+    };
+    if (gScope.addEventListener) {
+      gScope.addEventListener('message', handleMessage, true);
+    } else {
+      gScope.attachEvent('onmessage', handleMessage);
+    }
+  } else if (gScope.MessageChannel) {
+    // WebWorker MessageChannel
+    const channel = new gScope.MessageChannel();
+    channel.port1.onmessage = (event: any) => {
+      if (timeouts.length > 0) {
+        return timeouts.shift()!();
+      }
+    };
+    bfsSetImmediate = (fn: () => void) => {
+      timeouts.push(fn);
+      channel.port2.postMessage('');
+    };
+  } else {
+    bfsSetImmediate = function(fn: () => void) {
+      return setTimeout(fn, 0);
+    };
+  }
+}
+
+export default bfsSetImmediate;