Xbase++ Requires Chilkat v11.4.0+

Call a JavaScript Function Returning a Boolean

See more JavaScript Examples

Demonstrates how to call a JavaScript function that returns a boolean. Xbase++

LOCAL nSuccess
LOCAL oSbScript
LOCAL oJs
LOCAL oResult
LOCAL oFuncCall
LOCAL nRetval

nSuccess := 0

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

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

oSbScript := CreateObject("Chilkat.StringBuilder")
oSbScript:Append("function isEven(number) { return number % 2 === 0; }")

oJs := CreateObject("Chilkat.Js")

oResult := CreateObject("Chilkat.JsonObject")
oResult:EmitCompact := 0

//  Call Eval to add the function to the context's global object
nSuccess := oJs:Eval(oSbScript, oResult)
IF (nSuccess == 0)
    //  Examine the result for an exception.
    ? oResult:Emit()

    //  Also examine the LastErrorText.
    ? oJs:LastErrorText
    oSbScript:destroy()
    oJs:destroy()
    oResult:destroy()
    RETURN
ENDIF

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

oFuncCall := CreateObject("Chilkat.JsonObject")

//  Create JSON specifying the function name and arguments

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

oFuncCall:UpdateString("name", "isEven")
oFuncCall:UpdateInt("args[0]", 8)

nSuccess := oJs:CallFunction(oFuncCall, oResult)
IF (nSuccess == 0)
    //  Examine the result for an exception.
    ? oResult:Emit()

    //  Also examine the LastErrorText.
    ? oJs:LastErrorText
    oSbScript:destroy()
    oJs:destroy()
    oResult:destroy()
    oFuncCall:destroy()
    RETURN
ENDIF

? oResult:Emit()

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

nRetval := oResult:BoolOf("value")
? Str(nRetval)

//  Output:
//  1

oSbScript:destroy()
oJs:destroy()
oResult:destroy()
oFuncCall:destroy()