Merge Page.evaluate and Page.evaluateAsync together

This patch makes Page.evaluate await promise if one is
returned by the evaluated code.

This makes the Page.evaluateAsync unneeded, so the patch
removes it.

Fixes #11.

docs/api.md

@@ -21,7 +21,6 @@
     - [page.setViewportSize(size)](#pagesetsizesize)
     - [page.viewportSize()](#pagesize)
     - [page.evaluate(fun, args)](#pageevaluatefun-args)
-    - [page.evaluateAsync(fun, args)](#pageevaluateasyncfun-args)
     - [page.evaluateOnInitialized(fun, args)](#pageevaluateoninitializedfun-args)
     - [page.screenshot(type[, clipRect])](#pagescreenshottype-cliprect)
     - [page.saveScreenshot(filePath[, clipRect])](#pagesavescreenshotfilepath-cliprect)
@@ -149,12 +148,6 @@ Pages could be closed by `page.close()` method.
 - `args` [<Array>](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array) Arguments to pass to  `fun`
 - returns: [<Promise<Object>>](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Promise) Promise which resolves to function return value
 
-#### page.evaluateAsync(fun, args)
-
-- `fun` [<Function>](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function) Function to be evaluated in browser context
-- `args` [<Array>](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array) Arguments to pass to  `fun`
-- returns: [<Promise<Object>>](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Promise) Promise which resolves to function
-
 #### page.evaluateOnInitialized(fun, args)
 
 - `fun` [<Function>](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function) Function to be evaluated in browser context

lib/Page.js

@@ -89,7 +89,7 @@ class Page extends EventEmitter {
      * @return {!Promise}
      */
     async addScriptTag(url) {
-        return this.evaluateAsync(addScriptTag, url);
+        return this.evaluate(addScriptTag, url);
 
         /**
          * @param {string} url
@@ -125,7 +125,7 @@ class Page extends EventEmitter {
 
         var sourceURL = '__in_page_callback__' + name;
         this._sourceURLToPageCallback.set(sourceURL, new InPageCallback(name, callback));
-        var text = helpers.evaluationString(inPageCallback, [name], false /* awaitPromise */, sourceURL);
+        var text = helpers.evaluationString(inPageCallback, [name], false /* wrapInPromise */, sourceURL);
         await Promise.all([
             this._client.send('Debugger.enable', {}),
             this._client.send('Page.addScriptToEvaluateOnLoad', { scriptSource: text }),
@@ -326,25 +326,32 @@ class Page extends EventEmitter {
      * @return {!Promise<(!Object|undefined)>}
      */
     async evaluate(fun, ...args) {
-        var response = await helpers.evaluate(this._client, fun, args, false /* awaitPromise */);
+        var code = helpers.evaluationString(fun, args, false /* wrapInPromise */);
+        var response = await this._client.send('Runtime.evaluate', {
+            expression: code
+        });
         if (response.exceptionDetails) {
             this._handleException(response.exceptionDetails);
             return;
         }
-        return response.result.value;
+        var remoteObject = response.result;
+        if (remoteObject.type !== 'object')
+            return remoteObject.value;
+        var isPromise = remoteObject.type === 'object' && remoteObject.subtype === 'promise';
+        var response = await this._client.send('Runtime.callFunctionOn', {
+            objectId: remoteObject.objectId,
+            functionDeclaration: 'function() { return this; }',
+            returnByValue: true,
+            awaitPromise: isPromise
+        });
+        await this._client.send('Runtime.releaseObject', {
+            objectId: remoteObject.objectId
+        });
+        if (response.exceptionDetails) {
+            this._handleException(response.exceptionDetails);
+            return;
         }
 
-    /**
-     * @param {function()} fun
-     * @param {!Array<*>} args
-     * @return {!Promise<(!Object|undefined)>}
-     */
-    async evaluateAsync(fun, ...args) {
-        var response = await helpers.evaluate(this._client, fun, args, true /* awaitPromise */);
-        if (response.exceptionDetails) {
-            this._handleException(response.exceptionDetails);
-            return;
-        }
         return response.result.value;
     }
 
@@ -354,7 +361,7 @@ class Page extends EventEmitter {
      * @return {!Promise}
      */
     async evaluateOnInitialized(fun, ...args) {
-        var code = helpers.evaluationString(fun, args, false);
+        var code = helpers.evaluationString(fun, args, false /* wrapInPromise */);
         await this._client.send('Page.addScriptToEvaluateOnLoad', {
             scriptSource: code
         });

lib/helpers.js

@@ -74,14 +74,14 @@ var helpers = module.exports = {
     /**
      * @param {function()} fun
      * @param {!Array<*>} args
-     * @param {boolean} awaitPromise
+     * @param {boolean} wrapInPromise
      * @param {string=} sourceURL
      * @return {string}
      */
-    evaluationString: function(fun, args, awaitPromise, sourceURL) {
+    evaluationString: function(fun, args, wrapInPromise, sourceURL) {
         var argsString = args.map(x => JSON.stringify(x)).join(',');
         var code = `(${fun.toString()})(${argsString})`;
-        if (awaitPromise)
+        if (wrapInPromise)
             code = `Promise.resolve(${code})`;
         if (sourceURL)
             code += `\n//# sourceURL=${sourceURL}`;

test/test.js

@@ -45,15 +45,26 @@ describe('Puppeteer', function() {
         page.close();
     });
 
-    it('Page.evaluate', SX(async function() {
+    describe('Page.evaluate', function() {
+        it('should work', SX(async function() {
             var result = await page.evaluate(() => 7 * 3);
             expect(result).toBe(21);
         }));
-
+        it('should await promise', SX(async function() {
-    it('Page.evaluateAsync', SX(async function() {
+            var result = await page.evaluate(() => Promise.resolve(8 * 7));
-        var result = await page.evaluateAsync(() => Promise.resolve(8 * 7));
             expect(result).toBe(56);
         }));
+        it('should work from-inside inPageCallback', SX(async function() {
+            // Setup inpage callback, which calls Page.evaluate
+            await page.setInPageCallback('callController', async function(a, b) {
+                return await page.evaluate((a, b) => a * b, a, b);
+            });
+            var result = await page.evaluate(function() {
+                return callController(9, 3);
+            });
+            expect(result).toBe(27);
+        }));
+    });
 
     it('Page Events: ConsoleMessage', SX(async function() {
         var msgs = [];