From afb096cfd7b8b087b889822831a972552ebf6694 Mon Sep 17 00:00:00 2001
From: Pavel Feldman <pfeldman@chromium.org>
Date: Tue, 11 Jul 2017 16:25:25 -0700
Subject: [PATCH] Disable DOM domain after each operation. (#71)

It's very heavy to have DOM domain enabled. This patch keeps DOM domain disabled after each use.
---
 lib/Page.js | 86 +++++++++++++++++++++++++----------------------------
 1 file changed, 40 insertions(+), 46 deletions(-)

diff --git a/lib/Page.js b/lib/Page.js
index 4789e7c3be6..12d723bfb0a 100644
--- a/lib/Page.js
+++ b/lib/Page.js
@@ -61,8 +61,6 @@ class Page extends EventEmitter {
     this._screenDPI = screenDPI;
     /** @type {!Map<string, function>} */
     this._inPageCallbacks = new Map();
-    /** @type {?Promise<number>} */
-    this._rootNodeIdPromise = null;
 
     this._screenshotTaskChain = Promise.resolve();
 
@@ -80,7 +78,6 @@ class Page extends EventEmitter {
     client.on('Runtime.consoleAPICalled', event => this._onConsoleAPI(event));
     client.on('Page.javascriptDialogOpening', event => this._onDialog(event));
     client.on('Runtime.exceptionThrown', exception => this._handleException(exception.exceptionDetails));
-    client.on('DOM.documentUpdated', event => this._rootNodeIdPromise = null);
   }
 
   /**
@@ -492,25 +489,14 @@ class Page extends EventEmitter {
     await this._client.dispose();
   }
 
-  /**
-   * @return {!Promise<number>}
-   */
-  _rootNodeId() {
-    if (!this._rootNodeIdPromise) {
-      this._rootNodeIdPromise = this._client.send('DOM.getDocument', {
-        depth: 0
-      }).then(obj => obj.root.nodeId);
-    }
-    return this._rootNodeIdPromise;
-  }
-
   /**
    * @param {string} selector
    * @param {!Promise<number>}
    */
   async _querySelector(selector) {
+    let {root} = await this._client.send('DOM.getDocument', { depth: 1 });
     let {nodeId} = await this._client.send('DOM.querySelector', {
-      nodeId: await this._rootNodeId(),
+      nodeId: root.nodeId,
       selector
     });
     if (!nodeId)
@@ -523,28 +509,31 @@ class Page extends EventEmitter {
    * @param {!Promise}
    */
   async click(selector) {
-    let boxModel = (await this._client.send('DOM.getBoxModel', {
-      nodeId: await this._querySelector(selector)
-    })).model.content;
-    let x = Math.round((boxModel[0] + boxModel[4]) / (2 * this._screenDPI));
-    let y = Math.round((boxModel[1] + boxModel[5]) / (2 * this._screenDPI));
+    try {
+      const nodeId = await this._querySelector(selector);
+      let boxModel = (await this._client.send('DOM.getBoxModel', { nodeId })).model.content;
+      let x = Math.round((boxModel[0] + boxModel[4]) / 2);
+      let y = Math.round((boxModel[1] + boxModel[5]) / 2);
 
-    this._client.send('Input.dispatchMouseEvent', {
-      type: 'mouseMoved',
-      x, y
-    });
-    this._client.send('Input.dispatchMouseEvent', {
-      type: 'mousePressed',
-      button: 'left',
-      x, y,
-      clickCount: 1
-    });
-    await this._client.send('Input.dispatchMouseEvent', {
-      type: 'mouseReleased',
-      button: 'left',
-      x, y,
-      clickCount: 1
-    });
+      this._client.send('Input.dispatchMouseEvent', {
+        type: 'mouseMoved',
+        x, y
+      });
+      this._client.send('Input.dispatchMouseEvent', {
+        type: 'mousePressed',
+        button: 'left',
+        x, y,
+        clickCount: 1
+      });
+      await this._client.send('Input.dispatchMouseEvent', {
+        type: 'mouseReleased',
+        button: 'left',
+        x, y,
+        clickCount: 1
+      });
+    } finally {
+      await this._client.send('DOM.disable');
+    }
   }
 
   /**
@@ -552,9 +541,12 @@ class Page extends EventEmitter {
    * @param {!Promise}
    */
   async focus(selector) {
-    await this._client.send('DOM.focus', {
-      nodeId: await this._querySelector(selector)
-    });
+    try {
+      const nodeId = await this._querySelector(selector);
+      await this._client.send('DOM.focus', { nodeId });
+    } finally {
+      await this._client.send('DOM.disable');
+    }
   }
 
   /**
@@ -591,14 +583,16 @@ class Page extends EventEmitter {
 
   /**
    * @param {string} selector
-   * @param {!Array<string>} filePaths
+   * @param {!Array<string>} files
    * @return {!Promise}
    */
-  async uploadFile(selector, ...filePaths) {
-    await this._client.send('DOM.setFileInputFiles', {
-      nodeId: await this._querySelector(selector),
-      files: filePaths
-    });
+  async uploadFile(selector, ...files) {
+    try {
+      const nodeId = await this._querySelector(selector);
+      await this._client.send('DOM.setFileInputFiles', { nodeId, files });
+    } finally {
+      await this._client.send('DOM.disable');
+    }
   }
 }