Visual Basic 6.0 Requires Chilkat v11.4.0+

Call a JavaScript Function Returning a Boolean

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Demonstrates how to call a JavaScript function that returns a boolean. Visual Basic 6.0

Dim success As Long
success = 0

'  This is the JavaScript function we'll call:

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

Dim sbScript As New ChilkatStringBuilder
success = sbScript.Append("function isEven(number) { return number % 2 === 0; }")

Dim js As New ChilkatJs

Dim result As New ChilkatJsonObject
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.
    Debug.Print result.Emit()

    '  Also examine the LastErrorText.
    Debug.Print js.LastErrorText
    Exit Sub
End If

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

Dim funcCall As New ChilkatJsonObject

'  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.
    Debug.Print result.Emit()

    '  Also examine the LastErrorText.
    Debug.Print js.LastErrorText
    Exit Sub
End If

Debug.Print result.Emit()

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

Dim retval As Long
retval = result.BoolOf("value")
Debug.Print retval

'  Output:
'  1