Delphi ActiveX

Call a JavaScript Function Passing an Array Argument

See more JavaScript Examples

Demonstrates how to call a JavaScript function with an argument that is an array. 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;
argsArray: TChilkatJsonArray;
arg: TChilkatJsonArray;
sbOut: TChilkatStringBuilder;

begin
success := 0;

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

// function calculateTotal(numbers) {
//   console.log(numbers);
//   let total = 0;
//   
//   // Loop through every number in the array
//   for (const num of numbers) {
//     console.log(num);
//     total += num;
//   }
//   
//   return total;
// }

sbScript := TChilkatStringBuilder.Create(Self);
success := sbScript.LoadFile('js_function_array_arg.js','utf-8');
if (success = 0) then
  begin
    Memo1.Lines.Add(sbScript.LastErrorText);
    Exit;
  end;

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 calculateTotal(numbers)

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

// Create JSON specifying the function name and arguments
// In this case, there is only 1 argument, and it is an array.

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

// Create the arguments array.
argsArray := TChilkatJsonArray.Create(Self);

// The 1st argument in the arguments array is itself an array.
// Passing -1 indicates to append to the array.
arg := TChilkatJsonArray.Create(Self);
argsArray.AddArrayAt2(-1,arg.ControlInterface);

// Fill in the values for the 1st argument.
arg.AddNumberAt(-1,'10.50');
arg.AddNumberAt(-1,'20.00');
arg.AddNumberAt(-1,'5.25');

// Add the "args" array to the funcCall.
funcCall.AppendArrayCopy('args',argsArray.ControlInterface);

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

// The funcCall is as follows.  Notice that the 1st (and only) argument is an array.

// {
//   "name": "calculateTotal",
//   "args": [
//     [
//       10.50,
//       20.00,
//       5.25
//     ]
//   ]
// }

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());

// Result:
// {
//   "type": "double",
//   "value": 35.75
// }

// The function also emitted text to the console.

sbOut := TChilkatStringBuilder.Create(Self);
js.ConsoleOutputSb(sbOut.ControlInterface);
Memo1.Lines.Add(sbOut.GetAsString());

// Output:
// 10.5,20,5.25
// 10.5
// 20
// 5.25

// -----------------------------------------------------------
// Note: If the array argument is simple, this is an alternative
// and simpler way of creating the funcCall:

funcCall.Clear();
funcCall.UpdateString('name','calculateTotal');
funcCall.UpdateNumber('args[0][0]','10.50');
funcCall.UpdateNumber('args[0][1]','20.00');
funcCall.UpdateNumber('args[0][2]','5.25');
Memo1.Lines.Add(funcCall.Emit());
end;