Fixes #169 - emit ready ack for race condition (#170)

* fixes #169 - Add ack event when ready event is received, get rid of superfluous event listeners #169
* bumped version to 1.1.8 #169

README.md

@@ -176,6 +176,22 @@ In your application, at the point which the view is ready for rendering
 document.body.dispatchEvent(new Event('view-ready'))
 ```
 
+**Warning:** It is possible that your application will be ready and emit the event before the main electron process has had a chance execute the javascript in the renderer process which listens for this event.  
+
+If you are finding that the [event is not effective](https://github.com/fraserxu/electron-pdf/issues/169) and your page waits until the full timeout has occurred, then you should use `setInterval` to emit the event until it is acknowledged like so:
+
+```javascript
+  var eventEmitInterval = setInterval(function () {
+    document.dispatchEvent(new Event('ready'))
+  }, 25)
+
+  document.body.addEventListener('view-ready-ack', function(){
+    clearInterval(eventEmitInterval)
+  })
+```
+
+When the main process first receives your ready event it will emit a single acknowlegement on `document.body` with whatever event name you are using suffixed with `-ack`.  So the default would be `view-ready-ack`
+
 #### Observing your own event
 
 If the page you are rending is under your control, and you wish to modify the behavior

lib/exportJob.js

@@ -119,10 +119,7 @@ class ExportJob extends EventEmitter {
         this._initializeWindowForResource()
         const targetFile = this._getTargetFile(i)
         const generateFunction = this._generateOutput.bind(this, win, targetFile, pageDone)
-        const waitFunction = this._waitForPage.bind(this, win, generateFunction, this.args.outputWait)
-        // Need a new listener to generate the resource
-        win.webContents.removeAllListeners('did-finish-load')
-        win.webContents.on('did-finish-load', waitFunction)
+        this._waitForPage(win, generateFunction, this.args.outputWait)
         this._loadURL(win, uriPath)
       })
     })
@@ -428,6 +425,9 @@ class ExportJob extends EventEmitter {
 
   /**
    * Injects a wait if defined before calling the generateFunction
+   * Electron will apply the javascript we provide after the page is loaded,
+   * we don't have to wire up event listeners
+   * (https://github.com/electron/electron/pull/5319)
    *
    * @param window used for JavaScript injection to emit event back through IPC
    * @param generateFunction called when view is ready
@@ -468,6 +468,8 @@ class ExportJob extends EventEmitter {
                  document.body.addEventListener('${eventName}', 
                    function(event) {
                      ipcRenderer.send('${IPC_MAIN_CHANNEL_RENDER}', '${this.jobId}', event.detail)
+                     // #169 - allows clients to send event until we acknowledge receipt
+                     document.dispatchEvent(new Event('${eventName}-ack'))
                    }
                  )`
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "electron-pdf",
-  "version": "1.1.7",
+  "version": "1.1.8",
   "description": "A command line tool to generate PDF from URL, HTML or Markdown files",
   "main": "lib/index.js",
   "scripts": {

test/event-test.html

@@ -28,10 +28,18 @@ <h1>Used to test responding to a ready event emitted on document</h1>
   table.style.transformOrigin = 'top left'
   table.style.transform='scale(.8)'
 
-  setTimeout(function () {
+  document.body.dispatchEvent(new CustomEvent('view-ready', {}))
+
+  /*  */
+  var eventEmitInterval = setInterval(function () {
 //    document.dispatchEvent(new Event('ready'))
-    document.body.dispatchEvent(new CustomEvent('ready', {}))
-  }, 500)
+    document.body.dispatchEvent(new CustomEvent('view-ready', {}))
+  }, 25)
+
+  document.body.addEventListener('view-ready-ack', function(){
+    clearInterval(eventEmitInterval)
+  })
+
 
 </script>
 </body>