Report page errors (#5)

piuccio · web-flow · commit a0e59ba97bd1 · 2017-12-21T14:45:36.000+09:00
diff --git a/README.md b/README.md
@@ -34,6 +34,7 @@ render(url, {
   delayLaunch: 0, // milliseconds
   delayPageLoad: 0, // milliseconds
   chromeFlags: [], // list of flags
+  onPageError() {} // callback
 });
 ```
 
@@ -42,6 +43,7 @@ The second parameter of `render` function can either be an array of chrome flags
 * `delayLaunch` Wait to launch Chrome browser, in case you need more time to set up the server
 * `delayPageLoad` Wait after the page load event for your JS to run
 * `chromeFlags` List of chrome flags
+* `onPageError` Function called when an uncaught exception happens within the page. You can use this function for instance to fail your build if error happens during the generation of the page
 
 
 ## Continuous integration
diff --git a/__tests__/prerender.test.js b/__tests__/prerender.test.js
@@ -1,4 +1,5 @@
 const render = require('../index');
+const http = require('http');
 
 describe('Pre-renderer', () => {
   it('pre-renders a web page', () => {
@@ -11,4 +12,46 @@ describe('Pre-renderer', () => {
       delayPageLoad: 100,
     })).resolves.toMatch(/google/i);
   });
+
+  it('reports console messages', () => {
+    const onPageError = jest.fn();
+    return listen(() => render('http://localhost:4100', { onPageError }))
+    .then((result) => {
+      expect(result).toMatch(/test page/);
+      expect(onPageError).toHaveBeenCalledWith(expect.any(Error));
+      const error = onPageError.mock.calls[0][0];
+      expect(error.message).toMatch(/object is not defined/);
+    });
+  })
 });
+
+function listen(cb) {
+  return new Promise((resolve, reject) => {
+    const server = http.createServer((req, res) => {
+      res.writeHead(200, {
+        'Content-Type': 'text/html'
+      });
+      res.end(`
+        <html>
+          <head>
+            <title>test page</title>
+          </head>
+          <body>
+            <script>
+              object.fn();
+            </script>
+          </body>
+        </html>
+        `);
+      })
+      .listen(4100, () => {
+        cb().then((args) => {
+          server.close();
+          resolve(args);
+        }).catch((err) => {
+          server.close();
+          reject(err);
+        });
+      });
+  });
+}
diff --git a/index.js b/index.js
@@ -18,6 +18,9 @@ module.exports = function (source, options = {}) {
     'browser.newPage',
     (browser) => browser.newPage(),
 
+    `adding console listeners`,
+    (page) => page.on('pageerror', options.onPageError || noop) || page,
+
     `page.goto('${source}')`,
     (page) => page.goto(source)
   )
@@ -72,3 +75,5 @@ function wait(time) {
   }
   return Promise.resolve();
 }
+
+function noop () {}

Original file line number	Diff line number	Diff line change
`@@ -18,6 +18,9 @@ module.exports = function (source, options = {}) {`
`18`	`18`	`'browser.newPage',`
`19`	`19`	`(browser) => browser.newPage(),`
`20`	`20`
	`21`	+ `adding console listeners`,
	`22`	`+ (page) => page.on('pageerror', options.onPageError \|\| noop) \|\| page,`
	`23`	`+`
`21`	`24`	`page.goto('${source}')`,
`22`	`25`	`(page) => page.goto(source)`
`23`	`26`	`)`
`@@ -72,3 +75,5 @@ function wait(time) {`
`72`	`75`	`}`
`73`	`76`	`return Promise.resolve();`
`74`	`77`	`}`
	`78`	`+`
	`79`	`+function noop () {}`