This branch of the V8 JavaScript Engine features a highly experimental implementation of the proposed Object.observe addition to ECMAScript.
- Object.observe strawman: http://wiki.ecmascript.org/doku.php?id=strawman:observe
The API provided by Object.observe is fairly low-level. For example, it requires that you separately observe each object that you wish to be notified about. For a more convenient interface that allows observation of an arbitrarily-deep hierarchy of objects, as well as more convenient observation of arrays, we recommend using the ChangeSummary library, which is built on top of Object.observe.
This is an experimental implementation of a not-yet-accepted proposed addition to ECMAScript. It's only meant to let developers get a feel for the API and elicit feedback, not to be the basis for any "real" projects.
Moreover, the added V8 code is very rough (expect crashes here and there). Various V8 optimizations (such as the inline cache) have been disabled in order to ensure proper operation. Performance testing of this branch should not be expected to yield valid results.
Pre-built versions of Chromium supporting Object.observe are available for download:
- Windows: https://commondatastorage.googleapis.com/chromium-browser-mdv/object-observe/Chromium_Win_object-observe.zip
- Mac: https://commondatastorage.googleapis.com/chromium-browser-mdv/object-observe/Chromium_Mac_object-observe.tgz
You can also build your own, by cloning this repo into a Chromium checkout. See below.
Or, you can build V8 on its own (including the d8 shell), by following the instructions at http://code.google.com/p/v8/wiki/BuildingWithGYP.
Follow the normal Chromium build instructions, but edit your .gclient file and add the following line to your "custom_deps" section:
"src/v8": None
Then remove the old v8, clone this repo, rerun gclient, and build:
$ cd src
$ rm -rf v8
$ git clone git://github.com/rafaelw/v8.git
$ gclient runhooks
$ ninja -C out/Release chrome # or whichever build system you use
The point of this implementation is to allow JavaScript developers to experiment with the feature and provide feedback in advance of the feature being included in the specification. Please provide feedback to the es-discuss mailing list. The email to es-discuss announcing the availability of this implementation is here.