Xojo Plugin 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. Xojo Plugin

Dim success As Boolean
success = False

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

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

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

Dim js As New Chilkat.Js

Dim result As New Chilkat.JsonObject
result.EmitCompact = False

//  Call Eval to add the function to the context's global object
success = js.Eval(sbScript,result)
If (success = False) Then
    //  Examine the result for an exception.
    System.DebugLog(result.Emit())

    //  Also examine the LastErrorText.
    System.DebugLog(js.LastErrorText)
    Return
End If

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

Dim funcCall As New 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 = False) Then
    //  Examine the result for an exception.
    System.DebugLog(result.Emit())

    //  Also examine the LastErrorText.
    System.DebugLog(js.LastErrorText)
    Return
End If

System.DebugLog(result.Emit())

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

Dim retval As Boolean
retval = result.BoolOf("value")
System.DebugLog(Str(retval))

//  Output:
//  1