C++

Call a JavaScript Function Returning a Boolean

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

#include <CkStringBuilder.h>
#include <CkJs.h>
#include <CkJsonObject.h>

void ChilkatSample(void)
    {
    bool success = false;

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

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

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

    CkJs js;

    CkJsonObject 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.
        std::cout << result.emit() << "\r\n";

        //  Also examine the LastErrorText.
        std::cout << js.lastErrorText() << "\r\n";
        return;
    }

    //  ------------------------------------------------------------------------------
    //  Call the function isEven(8)

    CkJsonObject funcCall;

    //  Create JSON specifying the function name and arguments

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

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

    success = js.CallFunction(funcCall,result);
    if (success == false) {
        //  Examine the result for an exception.
        std::cout << result.emit() << "\r\n";

        //  Also examine the LastErrorText.
        std::cout << js.lastErrorText() << "\r\n";
        return;
    }

    std::cout << result.emit() << "\r\n";

    //  Output:
    //  {
    //    "type": "bool",
    //    "value": true
    //  }

    bool retval = result.BoolOf("value");
    std::cout << retval << "\r\n";

    //  Output:
    //  true
    }