(C++) Call a JavaScript Function Returning a String

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

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#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!
    }