Xojo Plugin

Prevent JavaScript Infinite Loops

See more JavaScript Examples

Demonstrates how prevent infinite loops or prevent the JavaScript from running for a longer amount of time than allowed. Xojo Plugin

Dim success As Boolean
success = False

//  This is the JavaScript we'll run:

//  console.log('Starting infinite loop...'); while(true) {};

Dim sbScript As New Chilkat.StringBuilder
success = sbScript.Append("console.log('Starting infinite loop...'); while(true) {};")

Dim js As New Chilkat.Js

//  Set a limit on the amount of time (in seconds) the script is allowed to run.
//  If the JavaScript takes longer than this amount of time, then Chilkat kills the script without crashing the host program.
//  The default value of TimeoutSeconds is 0, which indicates no limit.
//  For this example, set a limit of 2 seconds.
js.TimeoutSeconds = 2

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

//  Run the script..
success = js.Eval(sbScript,result)
If (success = False) Then
    //  Examine the result for an exception.
    System.DebugLog(result.Emit())

    //  The result contains this:

    //  	{
    //  	  "exception": {
    //  	    "message": "interrupted - JavaScript exceeded the Chilkat.Js.TimeoutSeconds",
    //  	    "stack": [
    //  	      {
    //  	        "func": "<eval>",
    //  	        "file": "<input>",
    //  	        "line": 1,
    //  	        "col": 8
    //  	      }
    //  	    ]
    //  	  }
    //  	}

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

//  We should never get here..
System.DebugLog("Succeeded.")
System.DebugLog(result.Emit())

JavaScript

console.log('Starting infinite loop...');
while(true) {};