Xojo Plugin

JavaScript console using Callbacks

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Demonstrates console output using Chilkat JavaScript with callbacks. Xojo Plugin

Class MyJs
    Inherits Chilkat.Js

    Sub ProgressInfo(name As String, value As String)
        System.DebugLog(name + ": " + value)
    End Sub

End Class

Dim success As Boolean
success = 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
    System.DebugLog(sbScript.LastErrorText)
    Return
End If

Dim js As New MyJs
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
    System.DebugLog(sbScript.LastErrorText)
    Return
End If

//  We can look at the result, which is "undefined", which is normal and expected.
System.DebugLog(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"}

JavaScript

// 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)