(VB.NET) JavaScript console using Callbacks

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Note: This example requires Chilkat v11.4.0 or greater.

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' ProgressInfo callback method.
Private Sub js_OnProgressInfo(sender As Object, args As Chilkat.ProgressInfoEventArgs) Handles js.OnProgressInfo

    Dim name As String = args.Name
    Dim value As String = args.Value
        Debug.WriteLine(name & ": " & value)
End Sub

private Sub ChilkatExample()

    Dim success As Boolean = False

    ' This example demonstrates using the built-in console object.
    ' The Javascript run in this example is shown below.



    ' Load the JavaScript from a file.
    Dim sbScript As New Chilkat.StringBuilder
    success = sbScript.LoadFile("qa_data/js_tests/test_console.js","utf-8")
    If (success = False) Then
        Debug.WriteLine(sbScript.LastErrorText)
        Exit Sub
    End If


    Dim WithEvents js As New Chilkat.Js
    Dim result As New Chilkat.JsonObject

    ' Run the JavaScript
    ' Results (not console output) go to result.
    ' Note: Eval returns the completion value of the script. This is generally the value of the last evaluated expression.
    ' In this case, the last evaluated expression is console.log which does not calculate a value. Therefore, it returns undefined.
    success = js.Eval(sbScript,result)
    If (success = False) Then
        Debug.WriteLine(sbScript.LastErrorText)
        Exit Sub
    End If


    ' We can look at the result, which is "undefined", which is normal and expected.
    Debug.WriteLine(result.Emit())
    ' The result JSON is: {"type":"undefined","value":"undefined"}

    ' The console output is received using ProgressInfo callbacks.
    ' The output is:

    ' log: Hello World, 248, 12.05
    ' 
    ' error: foo:bar baz
    ' 
    ' warn: 1 2 3
    ' 
    ' log: %% %s
    ' 
    ' log: myApp: {
    '   "appName": "Example",
    '   "version": 1,
    '   "isDebug": true,
    '   "supportedTypes": [
    '     "string",
    '     "number",
    '     "object"
    '   ],
    '   "settings": {
    '     "maxWidgets": 1024,
    '     "allowIO": true
    '   }
    ' }
    ' 
    ' log: App: myApp (Version 1)
    ' 
    ' {"type":"undefined","value":"undefined"}

End Sub

// Chilkat Js console emits CRLF line endings on Windows, and LF line endings on non-Windows.

console.log("Hello %s, %d, %f", "World", 248, 12.05);
// Output: Hello World, 248, 12.05

// If there are more arguments than the number of specifiers, the extra arguments are output, separated by spaces:
console.error('%s:%s', 'foo', 'bar', 'baz');
// Output: foo:bar baz

// If the first argument does not contain a valid format specifier, outputs a string that is the concatenation of all arguments separated by spaces:
console.warn(1,2,3);
// Output: 1 2 3

//If only one argument is passed, it is returned as it is without any formatting:
console.log("%% %s");
// Output: %% %s

const myApp = {
    appName: "Example",
    version: 1.0,
    isDebug: true,
    supportedTypes: ["string", "number", "object"],
    settings: {
       "maxWidgets": 1024,
        allowIO: true
    }
};

// %O: Emits the same as JSON.stringify(myConfig, null, 2)
console.log("myApp: %O", myApp);
// Output:
// myApp: {
//   "appName": "Example",
//   "version": 1,
//   "isDebug": true,
//   "supportedTypes": [
//     "string",
//     "number",
//     "object"
//   ],
//   "settings": {
//     "maxWidgets": 1024,
//     "allowIO": true
//   }
// }

console.log("App: %s (Version %d)", myApp.appName, myApp.version);
// Output: App: Example (Version 1)