DataFlex

Call a JavaScript Function Returning a String

See more JavaScript Examples

Demonstrates how to call a JavaScript function that returns a string. DataFlex

Use ChilkatAx-win32.pkg

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

    Move False To iSuccess

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

    // function greet(name) {
    //     return "Hello, " + name + "!";
    // }

    Get Create (RefClass(cComChilkatStringBuilder)) To hoSbScript
    If (Not(IsComObjectCreated(hoSbScript))) Begin
        Send CreateComObject of hoSbScript
    End
    Get ComAppend Of hoSbScript 'function greet(name) { return "Hello, " + name + "!"; }' To iSuccess

    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 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

    // ------------------------------------------------------------------------------
    // Call the function greet("Michael")

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

    // Create JSON specifying the function name and arguments

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

    Get ComUpdateString Of hoFuncCall "name" "greet" To iSuccess
    Get ComUpdateString Of hoFuncCall "args[0]" "Michael" To iSuccess

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

    Get ComStringOf Of hoResult "value" To sRetval
    Showln sRetval

    // Output:
    // Hello, Michael!


End_Procedure