Embedding ChakraCore

ChakraCore can be embedded via JavaScript Runtime (JSRT) APIs. This document goes through the basics of embedding with a Hello-world sample to get you started. To learn more about JSRT, visit JavaScript Runtime (JSRT) Overview.

Before you start

You should first clone and build ChakraCore. There are a few files that you will need,

1. CharkaCore.h and chakracommon.h from lib\jsrt\, which are the headers.
2. CharkaCore.lib and ChakraCore.dll from Build\VcBuild\bin\[platform+output]\.

C# users only need ChakraCore.dll.

Use JSRT with Visual Studio

To use JSRT in a C++ project:

1. Copy the headers into your project
2. #include "chakracore.h" in your project.
3. In Visual Studio, go to <your project> > Properties > Configuration Properties > Linker > Input > Additional Dependencies, and add a reference to ChakraCore.lib.
4. Copy ChakraCore.dll to the project output directory.

To use JSRT in a C# project:

1. Copy ChakraCore.dll to the project output directory.
2. In general, use PInvoke to call JSRT APIs. You can copy a wrapper from our sample. Sometimes, there may be new APIs that we have not yet added to the wrapper, but you can import from ChakraCore.dll like this,

[DllImport("ChakraCore.dll")] 
internal static extern JavaScriptErrorCode JsCreateRuntime(JavaScriptRuntimeAttributes attributes, JavaScriptThreadServiceCallback threadService, out JavaScriptRuntime runtime); 

Alternatively, you can also try using a higher level JSRT-WinRT WinRT Component.

Hello World!

A sample to help you understand how to embed ChakraCore with JSRT APIs. For C# users, please refer to the next section.

#include "chakracore.h"
#include <string>
#include <iostream>

using namespace std;

int main()
{
    JsRuntimeHandle runtime;
    JsContextRef context;
    JsValueRef result;
    unsigned currentSourceContext = 0;

    // Your script; try replace hello-world with something else
    wstring script = L"(()=>{return \'Hello world!\';})()";

    // Create a runtime. 
    JsCreateRuntime(JsRuntimeAttributeNone, nullptr, &runtime);

    // Create an execution context. 
    JsCreateContext(runtime, &context);

    // Now set the current execution context.
    JsSetCurrentContext(context);

    // Run the script.
    JsRunScript(script.c_str(), currentSourceContext++, L"", &result);

    // Convert your script result to String in JavaScript; redundant if your script returns a String
    JsValueRef resultJSString;
    JsConvertValueToString(result, &resultJSString);

    // Project script result back to C++.
    const wchar_t *resultWC;
    size_t stringLength;
    JsStringToPointer(resultJSString, &resultWC, &stringLength);

    wstring resultW(resultWC);
    cout << string(resultW.begin(), resultW.end()) << endl;
    
    return 0;
}

To build and run this sample,

1. Create a new C++ project in Visual Studio, complete the use JSRT with Visual Studio steps, and add the above code to a .cpp file. Alternatively, download this sample here and copy ChakraCore.dll to project output directory.
2. In Visual Studio, build the sample by pressing F6 or using Build > Build Solution.
3. Run the sample by pressing Ctrl+F5 or using Debug > Start Without Debugging.

Hello World! (C#)

C# version of the above Hello-world sample. Note that JSRT APIs are C++ APIs, this sample assumes a C# wrapper.

using System;
using System.Runtime.InteropServices;
// wrapper namespace
using ChakraHost.Hosting;

public class HelloWorld
{
    static void Main() {
        JavaScriptRuntime runtime;
        JavaScriptContext context;
        JavaScriptSourceContext currentSourceContext = JavaScriptSourceContext.FromIntPtr(IntPtr.Zero);
        JavaScriptValue result;

        // Your script, try replace the basic hello world with something else
        string script = "(()=>{return \'Hello world!\';})()";

        // Create a runtime. 
        Native.JsCreateRuntime(JavaScriptRuntimeAttributes.None, null, out runtime);
        
        // Create an execution context. 
        Native.JsCreateContext(runtime, out context);
        
        // Now set the execution context as being the current one on this thread.
        Native.JsSetCurrentContext(context);
        
        // Run the script.
        Native.JsRunScript(script, currentSourceContext++, "", out result);

        // Convert your script result to String in JavaScript; redundant if your script returns a String
        JavaScriptValue resultJSString;
        Native.JsConvertValueToString(result, out resultJSString);
        
        // Project script result in JS back to C#.
        IntPtr resultPtr;
        UIntPtr stringLength;
        Native.JsStringToPointer(resultJSString, out resultPtr, out stringLength);

        string resultString = Marshal.PtrToStringUni(resultPtr);
        Console.WriteLine(resultString);
    }
}

To build and run this sample,

1. Create a new C# project in Visual Studio, complete the use JSRT with Visual Studio steps, include a C# wrapper for JSRT and add the above code to a .cs file. Alternatively, download this sample here and copy ChakraCore.dll to project output directory. .
2. In Visual Studio, build the sample by pressing F6 or using Build > Build Solution.
3. Run the sample by pressing Ctrl+F5 or using Debug > Start Without Debugging.

More on JSRT

• JavaScript Runtime (JSRT) Overview
• JavaScript Runtime (JSRT) Reference
• JSRT and ChakraCore Samples