(C) Call a JavaScript Function Returning an Object

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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;

    success = FALSE;

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

    // function getSettings() {
    //     return {
    //         theme: "dark",
    //         notifications: true,
    //         version: 1.0
    //     };
    // }

    sbScript = CkStringBuilder_Create();
    CkStringBuilder_Append(sbScript,"function getSettings() {");
    CkStringBuilder_Append(sbScript,"    return {");
    CkStringBuilder_Append(sbScript,"        theme: \"dark\",");
    CkStringBuilder_Append(sbScript,"        notifications: true,");
    CkStringBuilder_Append(sbScript,"        version: 1.0");
    CkStringBuilder_Append(sbScript,"    };");
    CkStringBuilder_Append(sbScript,"}");

    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 getSettings()

    funcCall = CkJsonObject_Create();

    // Create JSON specifying the function name and arguments
    // The function has no arguments, so we only specify the name.

    // {
    //   "name": "getSettings",
    // }

    CkJsonObject_UpdateString(funcCall,"name","getSettings");

    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": "object",
    //   "value": {
    //     "theme": "dark",
    //     "notifications": true,
    //     "version": 1
    //   }
    // }

    // Examine the object's members
    printf("theme: %s\n",CkJsonObject_stringOf(result,"value.theme"));
    printf("notifications: %d\n",CkJsonObject_BoolOf(result,"value.notifications"));
    printf("version: %d\n",CkJsonObject_IntOf(result,"value.version"));

    // Output:
    // theme: dark
    // notifications: True
    // version: 1


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

    }