Delphi DLL

Call a JavaScript Function Returning an Object

See more JavaScript Examples

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

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

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
sbScript: HCkStringBuilder;
js: HCkJs;
result: HCkJsonObject;
funcCall: HCkJsonObject;

begin
success := False;

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

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

sbScript := CkStringBuilder_Create();
CkStringBuilder_Append(sbScript,'function getSettings() {');
CkStringBuilder_Append(sbScript,'    return {');
CkStringBuilder_Append(sbScript,'        theme: "dark",');
CkStringBuilder_Append(sbScript,'        notifications: true,');
CkStringBuilder_Append(sbScript,'        version: 1.0');
CkStringBuilder_Append(sbScript,'    };');
CkStringBuilder_Append(sbScript,'}');

js := CkJs_Create();

result := CkJsonObject_Create();
CkJsonObject_putEmitCompact(result,False);

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

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

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

funcCall := CkJsonObject_Create();

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

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

CkJsonObject_UpdateString(funcCall,'name','getSettings');

success := CkJs_CallFunction(js,funcCall,result);
if (success = False) then
  begin
    // Examine the result for an exception.
    Memo1.Lines.Add(CkJsonObject__emit(result));

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

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

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

// Examine the object's members
Memo1.Lines.Add('theme: ' + CkJsonObject__stringOf(result,'value.theme'));
Memo1.Lines.Add('notifications: ' + IntToStr(Ord(CkJsonObject_BoolOf(result,'value.notifications'))));
Memo1.Lines.Add('version: ' + IntToStr(CkJsonObject_IntOf(result,'value.version')));

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

CkStringBuilder_Dispose(sbScript);
CkJs_Dispose(js);
CkJsonObject_Dispose(result);
CkJsonObject_Dispose(funcCall);

end;