(Unicode C++) Call a JavaScript Function Returning a Boolean

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Note: This example requires Chilkat v11.4.0 or greater.

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

void ChilkatSample(void)
    {
    bool success = false;

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

    // function isEven(number) {
    //     return number % 2 === 0;
    // }

    CkStringBuilderW sbScript;
    sbScript.Append(L"function isEven(number) { return number % 2 === 0; }");

    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 isEven(8)

    CkJsonObjectW funcCall;

    // Create JSON specifying the function name and arguments

    // {
    //   "name": "isEven",
    //   "args": [ 8 ]
    // }

    funcCall.UpdateString(L"name",L"isEven");
    funcCall.UpdateInt(L"args[0]",8);

    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": "bool",
    //   "value": true
    // }

    bool retval = result.BoolOf(L"value");
    wprintf(L"%d\n",retval);

    // Output:
    // true
    }