Microsoft/ChakraCore

ChakraCore is the core part of the Chakra Javascript engine that powers Microsoft Edge

Grahame Grieve

@grahamegrieve

so I'm dense, or out of my depth here... I get what I think is the object you are talking about using JsGetAndClearException(obj). Using JsConvertValueToString/JsStringToPointer, I get the string I referred to above. So then I try to get the line property from it - using JsGetPropertyIdFromName and then JsGetProperty - and I get undefined for the value of the property.

Grahame Grieve

@grahamegrieve

no. I had to use JsCreatePropertyId instead of JsGetPropertyIdFromName. Why that is is not at all obvious from the documentation.

Ondrej Kelle

@tondrej

@grahamegrieve if you're using Pascal in chakracore-delphi you could pass the result of JsParse to ChakraCoreCheck which would raise an exception in your host app based on the error object, with properties like Line, Column, Source, URL.

Richard

@rhuanjl

JsGetPropertyIdFromName is marked as a windows only API because it expects a pointer to a row of char16 as the input string vs JsCreatePropertyId which takes a pointer to a row of char

Assuming you're using chakracore I generally would reccomend avoiding the APIs in ChakraCommonWindows.h; stick to the APIs in ChakraCommon.h and ChakraCore.h

Grahame Grieve

@grahamegrieve

well, I just switched to using your wrappers. Switching to the full code is a step too far for now

@tondrej

I'll try to stick to the non-windows API. But... do they solely differ by parameter type? or is there more to it?

Ondrej Kelle

@tondrej

@grahamegrieve Fair enough, then you might still benefit from using the ChakraCoreUtils unit which is just a very thin layer on top of the API, with some helper routines converting from/to some Pascal types and raising exceptions.

Ondrej Kelle

@tondrej

And it already has helpers to get properties by name or symbol, using none of the Windows-specific APIs.

Richard

@rhuanjl

there's nothing that needs the window's specific api unless you're using the chakra.dll which ships with windows rather than chakracore

Richard

@rhuanjl

the API seems perfectly usable without wrapper layers IMO though I guess if it saves you some time or if you're not working in C it may make sense

Ondrej Kelle

@tondrej

Thanks @rhuanjl - agreed! That's exactly the case here - the wrapper layers are only for convenience when using ChakraCore from Delphi or Free Pascal (not C).

CatCatCatDog

@CatCatCatDog

Guys, has anyone tried heap trace for ChakraCore? i mean, i want know where heap allocate with valgrind?

Bruce Pascoe

@fatcerberus

Valgrind requires you to compile CC using the --valgrind option—which is currently broken :(

Otherwise valgrind doesn’t like the 32GB address space reservation and suicides

“Out of memory”

CatCatCatDog

@CatCatCatDog

Ok, thanks

AdobeFlashMan

@AdobeFlashMan_twitter

Hey guys, I want using ChakraCore with static linking in MSVC, has anyone tried this? It only has dynamic linking by default.

Bruce Pascoe

@fatcerberus

Static linking doesn’t currently work on Windows sadly :(

Jimmy Thomson

@MSLaguana

It's not supported at the moment, although someone did try it out and get it mostly working from what I recall. They did have to make some changes (a number of things happen on dll load, which will need to be changed for static linkage)

Jimmy Thomson

@MSLaguana

I don't recall the name of that person/project though, unfortunately

AdobeFlashMan

@AdobeFlashMan_twitter

Thank you for your replies. Yes, I tried to figure out how to convert ChakraCore.vcxproj to a static linking vcxproj, but it seems like I need to do a lot of things to do this ( e.g. ChakraBinaryAutoSystemInfoInit ).

Richard

@rhuanjl

I think the working (though with some issues) static version of chakracore was part of this game engine project: https://github.com/Kode/Krom

nanjizal

@nanjizal

AdobeFlashMan, you may find https://github.com/Kode/openfl interesting, it's basically a minimal incomplete implemention of OpenFL implemented on top of Kha and potentially suitable for use with Krom. As you may know OpenFL is a Haxe implementation of the flash api and compiles both to c++ and js. Kha is more of a renderloop approach like say starling's renderTexture but cleaner. Kha code base is mixed js/c build but uses haxe ( or C++ ) for coding. Haxe is quite similar to as3 but arguably a better. Kha can target js or c++, it uses Krom as one possible target, I think it might be built into 'Kode Studio' a variant of Visual Code Studio and used for testing and debugging Kha and shaders. Anyway the way Kha uses Krom is with shaders recompiled ( https://github.com/Kode/krafix ) so there is no Dom support and it's purely a JS shader engine. I don't know anything about static linking etc... being more front end x-flash and now a haxe dev. But if your looking for a way to create applications and games with ChakraCore then Kha is definitely an option, if your used to Flash then you will find the text support good but very low level. For GPU graphics it's much cleaner simpler than flash stage3d and starling and allows many workflows perhaps look and Armory3d and the core library Iron as one possible approach.

sorry my grammer is not ideal.

Grahame Grieve

@grahamegrieve

is there anyway I can mark an object as immutable? so that you can't assign to properties on it?

this applies to both to objects I pass into the javascript engine, and some objects created by the javascript code

Grahame Grieve

@grahamegrieve

a related question: I expose an object of mine to javascript, so that myObj.prop refers through to "prop" on my internal object, and myObj.prop = "test" sets the value of the prop on my object. But if the user accidentally does myObj.propx = "test", chakra creates a new js prop "propx" on the js wrapper object. I haven't found a way to either prevent this or get notified about it, so the property gets lost and it's effectively a silent bug. What are my options here?

Ondrej Kelle

@tondrej

@grahamegrieve to mark an object as immutable, I think you could use Object.freeze(), for hooking property setters/getters perhaps you could use a Proxy or, if you only want to prevent adding new properties, Object.preventExtensions()

Grahame Grieve

@grahamegrieve

well, I didn't think of freeze() because of this: "Accessor properties (getters and setters) work the same (and still give the illusion that you are changing the value)" - unless I misunderstand what that means?

Bruce Pascoe

@fatcerberus

Well I mean if there’s a setter then you can’t magically make the setter not be called on assignment

Grahame Grieve

@grahamegrieve

hmm I'm having trouble calling freeze() on an object. The sequence seems like:

use JsCreatePropertyId to get the propertyId for 'freeze'
use JsGetProperty to get the function for the propertyId
use JsCallFunction passing the func with one parameter which is the object to freeze

.. and I get an ErrorInvalidArgument so I'm doing something wrong?

Jimmy Thomson

@MSLaguana

If you want to invoke the javascript equivalent of Object.freeze(foo), then you need to get a JsValueRef objectObject referencing the global Object, and make sure that you pass that as the this parameter of the freeze function, since the C api is somewhat like calling freeze.call(Object, yourObject)

Grahame Grieve

@grahamegrieve

hmm thanks. that seems obvious... but when I call JsGetProperty for the propertyId for 'freeze' in the return value from JsGetGlobalObject I get a JsUndefined?

Jimmy Thomson

@MSLaguana

JsGetGlobalObject is getting the global object, not the global Object object. E.g. JsGetGlobalObject is the window / "this" object at global scope, and that has an "Object" property which is the Object of Object.freeze that you need to get the property off

Ondrej Kelle

@tondrej

@grahamegrieve In a chakracore-delphi example (using ChakraCoreUtils unit), it would look like this: JsCallFunction('freeze', [], JsGetProperty(JsGlobal, 'Object'));

Ondrej Kelle

@tondrej

An example of a similar usage is here, calling Object.create(prototype)

Grahame Grieve

@grahamegrieve

k thanks all. Really appreciate the help

Bruce Pascoe

@fatcerberus

Is it necessary to pass Object as this? Most JS builtins don’t require this because their spec doesn’t need them to access this at all

For example you can safely call JSON.stringify without JSON being passed as ‘this’

Richard

@rhuanjl

You have to get Object in order to then get at its property freeze but you can then call freeze with an undefined this value

Bruce Pascoe

@fatcerberus

Yeah that’s what I thought thanks @rhuanjl

Also look into JsObjectGetProperty to avoid the need for the PropertyId rigamorole

Michael Holman

@MikeHolman

Does anyone use the JsSetObjectBeforeCollectCallback API?

Jimmy Thomson

@MSLaguana

@fatcerberus Sorry yes you're right; the important thing is that the yourObject can't be the first parameter, since that is the "this" parameter

Ondrej Kelle

@tondrej

@fatcerberus Thanks for the JsObjectGetProperty tip!

Grahame Grieve

@grahamegrieve

is there a way to get the engine to run in strict mode?

Bruce Pascoe

@fatcerberus

You could prepend "use strict"; to all the scripts you run

Where communities thrive

People

Repo info

Activity