DevTools: introduce object previews experiment

third_party/WebKit/Source/devtools/front_end/components/RemoteObjectPreviewFormatter.js

 // Copyright (c) 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 /**
  * @unrestricted
  */
 Components.RemoteObjectPreviewFormatter = class {
   /**
    * @param {!Protocol.Runtime.PropertyPreview} a
    * @param {!Protocol.Runtime.PropertyPreview} b
    * @return {number}
    */
   static _objectPropertyComparator(a, b) {
     if (a.type !== 'function' && b.type === 'function')
       return -1;
     if (a.type === 'function' && b.type !== 'function')
       return 1;
     return 0;
   }
 
   /**
    * @param {!Element} parentElement
    * @param {!Protocol.Runtime.ObjectPreview} preview
    */
   appendObjectPreview(parentElement, preview) {
     var description = preview.description;
-    if (preview.type !== 'object' || preview.subtype === 'null') {
+    if (preview.type !== 'object' || preview.subtype === 'null' || preview.subtype === 'regexp' ||
+        preview.subtype === 'error' || preview.subtype === 'internal#entry') {
       parentElement.appendChild(this.renderPropertyPreview(preview.type, preview.subtype, description));
       return;
     }
-    if (description && preview.subtype !== 'array')
-      parentElement.createTextChildren(description, ' ');
+    if (description) {
+      if (Runtime.experiments.isEnabled('objectPreviews')) {
+        var text = '';
+        if (preview.subtype === 'typedarray' || preview.subtype === 'map' || preview.subtype === 'set')
+          text = description.replace(/\[([0-9]+)\]|\(([0-9]+)\)/, '');
+        else if (preview.subtype !== 'array')
+          text = description;
+        var size = SDK.RemoteObject.arrayLength(preview) || SDK.RemoteObject.numEntries(preview);
+        if (size > 1)
+          text += '(' + size + ')';
+        if (text.length > 0)
+          parentElement.createChild('span', 'object-description').textContent = text + ' ';
+      } else if (preview.subtype !== 'array') {
+        parentElement.createTextChildren(description, ' ');
+      }
+    }
 
     var isArray = preview.subtype === 'array' || preview.subtype === 'typedarray';
-    parentElement.createTextChild(isArray ? '[' : '{');
+    var previewElement = parentElement.createChild('span', 'object-preview');
+    previewElement.createTextChild(isArray ? '[' : '{');
     if (preview.entries)
-      this._appendEntriesPreview(parentElement, preview);
+      this._appendEntriesPreview(previewElement, preview);
     else if (isArray)
-      this._appendArrayPropertiesPreview(parentElement, preview);
+      this._appendArrayPropertiesPreview(previewElement, preview);
     else
-      this._appendObjectPropertiesPreview(parentElement, preview);
+      this._appendObjectPropertiesPreview(previewElement, preview);
     if (preview.overflow)
-      parentElement.createChild('span').textContent = '\u2026';
-    parentElement.createTextChild(isArray ? ']' : '}');
+      previewElement.createChild('span').textContent = '\u2026';
+    previewElement.createTextChild(isArray ? ']' : '}');
   }
 
   /**
    * @param {string} description
    * @return {string}
    */
   _abbreviateFullQualifiedClassName(description) {
     var abbreviatedDescription = description.split('.');
     for (var i = 0; i < abbreviatedDescription.length - 1; ++i)
       abbreviatedDescription[i] = abbreviatedDescription[i].trimMiddle(3);
@@ skipping 166 matching lines @@
       span.createTextChildren('"', description.replace(/\n/g, '\u21B5'), '"');
       return span;
     }
 
     if (type === 'object' && !subtype) {
       span.textContent = this._abbreviateFullQualifiedClassName(description);
       span.title = description;
       return span;
     }
 
-    span.textContent = description;
+    span.setTextContentTruncatedIfNeeded(description);

[luoe, 2017/01/04 04:10:27]

With regexp and error types are going through here (see line 29), this will
be needed.

     return span;
   }
 };