Pascal (Lazarus/Delphi)

JavaScript console

See more JavaScript Examples

Demonstrates console output using Chilkat JavaScript. Pascal (Lazarus/Delphi)

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.Js,
  Chilkat.StringBuilder,
  Chilkat.JsonObject;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  sbScript: TStringBuilder;
  js: TJs;
  result: TJsonObject;
  sbOut: TStringBuilder;

begin
  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.
  sbScript := TStringBuilder.Create;
  success := sbScript.LoadFile('qa_data/js_tests/test_console.js','utf-8');
  if (success = False) then
    begin
      WriteLn(sbScript.LastErrorText);
      Exit;
    end;

  js := TJs.Create;
  result := TJsonObject.Create;

  //  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
    begin
      WriteLn(sbScript.LastErrorText);
      Exit;
    end;

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

  //  The console output is retrieved by calling ConsoleOutputSb
  sbOut := TStringBuilder.Create;
  js.ConsoleOutputSb(sbOut);
  WriteLn(sbOut.GetAsString());


  sbScript.Free;
  js.Free;
  result.Free;
  sbOut.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.