Unicode C++

Call a JavaScript Function Returning a String

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Demonstrates how to call a JavaScript function that returns a string. Unicode C++

#include <CkStringBuilderW.h>
#include <CkJsW.h>
#include <CkJsonObjectW.h>

void ChilkatSample(void)
    {
    bool success = false;

    //  This is the JavaScript function we'll call:

    //  function greet(name) {
    //      return "Hello, " + name + "!";
    //  }

    CkStringBuilderW sbScript;
    sbScript.Append(L"function greet(name) { return \"Hello, \" + name + \"!\"; }");

    CkJsW js;

    CkJsonObjectW result;
    result.put_EmitCompact(false);

    //  Call Eval to add the function to the context's global object
    success = js.Eval(sbScript,result);
    if (success == false) {
        //  Examine the result for an exception.
        wprintf(L"%s\n",result.emit());

        //  Also examine the LastErrorText.
        wprintf(L"%s\n",js.lastErrorText());
        return;
    }

    //  ------------------------------------------------------------------------------
    //  Call the function greet("Michael")

    CkJsonObjectW funcCall;

    //  Create JSON specifying the function name and arguments

    //  {
    //    "name": "greet",
    //    "args": [ "Michael" ]
    //  }

    funcCall.UpdateString(L"name",L"greet");
    funcCall.UpdateString(L"args[0]",L"Michael");

    success = js.CallFunction(funcCall,result);
    if (success == false) {
        //  Examine the result for an exception.
        wprintf(L"%s\n",result.emit());

        //  Also examine the LastErrorText.
        wprintf(L"%s\n",js.lastErrorText());
        return;
    }

    wprintf(L"%s\n",result.emit());

    //  Output:
    //  {
    //    "type": "string",
    //    "value": "Hello, Michael!"
    //  }

    const wchar_t *retval = result.stringOf(L"value");
    wprintf(L"%s\n",retval);

    //  Output:
    //  Hello, Michael!
    }