C++

Call a JavaScript Function Returning a String

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Demonstrates how to call a JavaScript function that returns a string. 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 greet(name) {
    //      return "Hello, " + name + "!";
    //  }

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

    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 greet("Michael")

    CkJsonObject funcCall;

    //  Create JSON specifying the function name and arguments

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

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

    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": "string",
    //    "value": "Hello, Michael!"
    //  }

    const char *retval = result.stringOf("value");
    std::cout << retval << "\r\n";

    //  Output:
    //  Hello, Michael!
    }