feat(runtime): support node 16 (#624)

.github/workflows/unit_test.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        node-version: [12.x, 14.x]
+        node-version: [12.x, 14.x, 16.x]
     steps:
       - name: Checkout
         uses: actions/checkout@v2

__tests__/server/middleware/__snapshots__/createRequestHtmlFragment.spec.js.snap

@@ -1,12 +1,5 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
-exports[`createRequestHtmlFragment should catch any errors and call the next middleware 1`] = `
-Array [
-  "error creating request HTML fragment for http://example.com/request",
-  [TypeError: Cannot read property 'dispatch' of undefined],
-]
-`;
-
 exports[`createRequestHtmlFragment should preload data for matched route components 1`] = `
 Array [
   Object {

__tests__/server/middleware/createRequestHtmlFragment.spec.js

@@ -245,6 +245,16 @@ describe('createRequestHtmlFragment', () => {
 
   it('should catch any errors and call the next middleware', () => {
     expect.assertions(3);
+    let error;
+    try {
+      let empty;
+      // Creating an error reading properties of undefined for tests to work in
+      // both Node 12 and 16 where the message has changed.
+      // eslint-disable-next-line no-unused-expressions
+      empty.dispatch;
+    } catch (err) {
+      error = err;
+    }
     const createRequestHtmlFragment = require(
       '../../../src/server/middleware/createRequestHtmlFragment'
     ).default;
@@ -255,7 +265,7 @@ describe('createRequestHtmlFragment', () => {
     console.error = jest.fn();
     middleware(req, res, next);
     expect(console.error).toHaveBeenCalled();
-    expect(console.error.mock.calls[0]).toMatchSnapshot();
+    expect(console.error.mock.calls[0]).toEqual(['error creating request HTML fragment for http://example.com/request', error]);
     expect(next).toHaveBeenCalled();
     /* eslint-enable no-console */
   });