(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 <C_CkStringBuilder.h>
#include <C_CkJs.h>
#include <C_CkJsonObject.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkStringBuilder sbScript;
    HCkJs js;
    HCkJsonObject result;
    HCkJsonObject funcCall;
    BOOL retval;

    success = FALSE;

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

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

    sbScript = CkStringBuilder_Create();
    CkStringBuilder_Append(sbScript,"function isEven(number) { return number % 2 === 0; }");

    js = CkJs_Create();

    result = CkJsonObject_Create();
    CkJsonObject_putEmitCompact(result,FALSE);

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

        // Also examine the LastErrorText.
        printf("%s\n",CkJs_lastErrorText(js));
        CkStringBuilder_Dispose(sbScript);
        CkJs_Dispose(js);
        CkJsonObject_Dispose(result);
        return;
    }

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

    funcCall = CkJsonObject_Create();

    // Create JSON specifying the function name and arguments

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

    CkJsonObject_UpdateString(funcCall,"name","isEven");
    CkJsonObject_UpdateInt(funcCall,"args[0]",8);

    success = CkJs_CallFunction(js,funcCall,result);
    if (success == FALSE) {
        // Examine the result for an exception.
        printf("%s\n",CkJsonObject_emit(result));

        // Also examine the LastErrorText.
        printf("%s\n",CkJs_lastErrorText(js));
        CkStringBuilder_Dispose(sbScript);
        CkJs_Dispose(js);
        CkJsonObject_Dispose(result);
        CkJsonObject_Dispose(funcCall);
        return;
    }

    printf("%s\n",CkJsonObject_emit(result));

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

    retval = CkJsonObject_BoolOf(result,"value");
    printf("%d\n",retval);

    // Output:
    // TRUE


    CkStringBuilder_Dispose(sbScript);
    CkJs_Dispose(js);
    CkJsonObject_Dispose(result);
    CkJsonObject_Dispose(funcCall);

    }