Pascal (Lazarus/Delphi)

Eval JavaScript Returning String

See more JavaScript Examples

Demonstrates getting the completion value of a JavaScript that returns a string. 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;

begin
  success := False;

  //  This example demonstrates getting the completion value of a script,
  //  where the last evaluated expression is a string.

  //  The Javascript run in this example is shown below.

  //  Load the JavaScript from a file.
  sbScript := TStringBuilder.Create;
  success := sbScript.LoadFile('js_eval_return_string.js','utf-8');
  if (success = False) then
    begin
      WriteLn(sbScript.LastErrorText);
      Exit;
    end;

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

  //  Run the JavaScript
  //  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 a string.
  success := js.Eval(sbScript,result);
  if (success = False) then
    begin
      WriteLn(js.LastErrorText);
      Exit;
    end;

  result.EmitCompact := False;
  WriteLn(result.Emit());

  //  Output:

  //  {
  //    "type": "string",
  //    "value": "Ready for Chilkat.Js"
  //  }


  sbScript.Free;
  js.Free;
  result.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.