Delphi ActiveX

Call a JavaScript Function Returning an Object

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Demonstrates how to call a JavaScript function that returns an object. Delphi ActiveX

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_TLB;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Integer;
sbScript: TChilkatStringBuilder;
js: TChilkatJs;
result: TChilkatJsonObject;
funcCall: TChilkatJsonObject;

begin
success := 0;

// This is the JavaScript function we'll call:

// function getSettings() {
//     return {
//         theme: "dark",
//         notifications: true,
//         version: 1.0
//     };
// }

sbScript := TChilkatStringBuilder.Create(Self);
sbScript.Append('function getSettings() {');
sbScript.Append('    return {');
sbScript.Append('        theme: "dark",');
sbScript.Append('        notifications: true,');
sbScript.Append('        version: 1.0');
sbScript.Append('    };');
sbScript.Append('}');

js := TChilkatJs.Create(Self);

result := TChilkatJsonObject.Create(Self);
result.EmitCompact := 0;

// Call Eval to add the function to the context's global object
success := js.Eval(sbScript.ControlInterface,result.ControlInterface);
if (success = 0) then
  begin
    // Examine the result for an exception.
    Memo1.Lines.Add(result.Emit());

    // Also examine the LastErrorText.
    Memo1.Lines.Add(js.LastErrorText);
    Exit;
  end;

// ------------------------------------------------------------------------------
// Call the function getSettings()

funcCall := TChilkatJsonObject.Create(Self);

// Create JSON specifying the function name and arguments
// The function has no arguments, so we only specify the name.

// {
//   "name": "getSettings",
// }

funcCall.UpdateString('name','getSettings');

success := js.CallFunction(funcCall.ControlInterface,result.ControlInterface);
if (success = 0) then
  begin
    // Examine the result for an exception.
    Memo1.Lines.Add(result.Emit());

    // Also examine the LastErrorText.
    Memo1.Lines.Add(js.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add(result.Emit());

// Output:
// {
//   "type": "object",
//   "value": {
//     "theme": "dark",
//     "notifications": true,
//     "version": 1
//   }
// }

// Examine the object's members
Memo1.Lines.Add('theme: ' + result.StringOf('value.theme'));
Memo1.Lines.Add('notifications: ' + IntToStr(Ord(result.BoolOf('value.notifications'))));
Memo1.Lines.Add('version: ' + IntToStr(result.IntOf('value.version')));

// Output:
// theme: dark
// notifications: True
// version: 1
end;