VBScript

Call a JavaScript Function Returning a Boolean

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Demonstrates how to call a JavaScript function that returns a boolean. VBScript

Dim fso, outFile
Set fso = CreateObject("Scripting.FileSystemObject")
'Create a Unicode (utf-16) output text file.
Set outFile = fso.CreateTextFile("output.txt", True, True)

success = 0

' This is the JavaScript function we'll call:

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

set sbScript = CreateObject("Chilkat.StringBuilder")
success = sbScript.Append("function isEven(number) { return number % 2 === 0; }")

set js = CreateObject("Chilkat.Js")

set result = CreateObject("Chilkat.JsonObject")
result.EmitCompact = 0

' Call Eval to add the function to the context's global object
success = js.Eval(sbScript,result)
If (success = 0) Then
    ' Examine the result for an exception.
    outFile.WriteLine(result.Emit())

    ' Also examine the LastErrorText.
    outFile.WriteLine(js.LastErrorText)
    WScript.Quit
End If

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

set funcCall = CreateObject("Chilkat.JsonObject")

' Create JSON specifying the function name and arguments

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

success = funcCall.UpdateString("name","isEven")
success = funcCall.UpdateInt("args[0]",8)

success = js.CallFunction(funcCall,result)
If (success = 0) Then
    ' Examine the result for an exception.
    outFile.WriteLine(result.Emit())

    ' Also examine the LastErrorText.
    outFile.WriteLine(js.LastErrorText)
    WScript.Quit
End If

outFile.WriteLine(result.Emit())

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

retval = result.BoolOf("value")
outFile.WriteLine(retval)

' Output:
' 1

outFile.Close