Delphi DLL Requires Chilkat v11.4.0+

Call a JavaScript Function Returning a Boolean

See more JavaScript Examples

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

var
success: Boolean;
sbScript: HCkStringBuilder;
js: HCkJs;
result: HCkJsonObject;
funcCall: HCkJsonObject;
retval: Boolean;

begin
success := False;

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

//  function isEven(number) {
//      return number % 2 === 0;
//  }

sbScript := CkStringBuilder_Create();
CkStringBuilder_Append(sbScript,'function isEven(number) { return number % 2 === 0; }');

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 isEven(8)

funcCall := CkJsonObject_Create();

//  Create JSON specifying the function name and arguments

//  {
//    "name": "isEven",
//    "args": [ 8 ]
//  }

CkJsonObject_UpdateString(funcCall,'name','isEven');
CkJsonObject_UpdateInt(funcCall,'args[0]',8);

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": "bool",
//    "value": true
//  }

retval := CkJsonObject_BoolOf(result,'value');
Memo1.Lines.Add(IntToStr(Ord(retval)));

//  Output:
//  1

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