DataFlex

Call a JavaScript Function Returning an Integer

See more JavaScript Examples

Demonstrates how to call a JavaScript function that returns an integer. DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Variant vSbScript
    Handle hoSbScript
    Handle hoJs
    Variant vResult
    Handle hoResult
    Variant vFuncCall
    Handle hoFuncCall
    Integer iRetval
    String sTemp1

    Move False To iSuccess

    // ----------------------------------------------------------------------------------
    // The Javascript function called in this example is shown at the bottom of this page.
    // -----------------------------------------------------------------------------------

    // In this example, we'll load the Javascript function definition from a file.
    // It doesn't need to come from a file.  It could just as easily be loaded from a string.
    Get Create (RefClass(cComChilkatStringBuilder)) To hoSbScript
    If (Not(IsComObjectCreated(hoSbScript))) Begin
        Send CreateComObject of hoSbScript
    End
    Get ComLoadFile Of hoSbScript "js_call_function.js" "utf-8" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoSbScript To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Note: Each instance of a Chilkat Js object automatically establishes
    // its own internal runtime and context.  Applications do not need to explicitly create
    // the JavaScript runtime or context.
    Get Create (RefClass(cComChilkatJs)) To hoJs
    If (Not(IsComObjectCreated(hoJs))) Begin
        Send CreateComObject of hoJs
    End

    Get Create (RefClass(cComChilkatJsonObject)) To hoResult
    If (Not(IsComObjectCreated(hoResult))) Begin
        Send CreateComObject of hoResult
    End
    Set ComEmitCompact Of hoResult To False

    // Call Eval to add the function (shown at the bottom of this page) to the context's global object
    Get pvComObject of hoSbScript to vSbScript
    Get pvComObject of hoResult to vResult
    Get ComEval Of hoJs vSbScript vResult To iSuccess
    If (iSuccess = False) Begin
        // Examine the result for an exception.
        Get ComEmit Of hoResult To sTemp1
        Showln sTemp1

        // Also examine the LastErrorText.
        Get ComLastErrorText Of hoJs To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get ComEmit Of hoResult To sTemp1
    Showln sTemp1

    // The expected output is "undefined":

    // {
    //   "type": "undefined",
    //   "value": "undefined"
    // }

    //    When Eval processes a script containing only a function declaration,
    //    it successfully performs the action (the function becomes defined).
    //    However, since the script consists of a statement that produces no value,
    //    the script's overall completion value is empty. In JavaScript, the
    //    absence of a value is represented by `undefined`.
    // 
    //    Therefore, the Eval call returns `undefined`.

    // ------------------------------------------------------------------------------
    // Call the function calculateScore("Player1", 10, 20)

    Get Create (RefClass(cComChilkatJsonObject)) To hoFuncCall
    If (Not(IsComObjectCreated(hoFuncCall))) Begin
        Send CreateComObject of hoFuncCall
    End

    // Create JSON defining the function call:

    // {
    //   "name": "calculateScore",
    //   "args": [ "Player1", 10, 20 ]
    // }

    Get ComUpdateString Of hoFuncCall "name" "calculateScore" To iSuccess
    Get ComUpdateString Of hoFuncCall "args[0]" "Player1" To iSuccess
    Get ComUpdateInt Of hoFuncCall "args[1]" 10 To iSuccess
    Get ComUpdateInt Of hoFuncCall "args[2]" 20 To iSuccess

    Set ComEmitCompact Of hoFuncCall To False
    Get ComEmit Of hoFuncCall To sTemp1
    Showln sTemp1

    Get pvComObject of hoFuncCall to vFuncCall
    Get pvComObject of hoResult to vResult
    Get ComCallFunction Of hoJs vFuncCall vResult To iSuccess
    If (iSuccess = False) Begin
        // Examine the result for an exception.
        Get ComEmit Of hoResult To sTemp1
        Showln sTemp1

        // Also examine the LastErrorText.
        Get ComLastErrorText Of hoJs To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get ComEmit Of hoResult To sTemp1
    Showln sTemp1

    // Output:

    // {
    //   "type": "int",
    //   "value": 37
    // }

    Get ComIntOf Of hoResult "value" To iRetval
    Showln "retval = " iRetval


End_Procedure