Delphi ActiveX

Call a JavaScript Function Passing an Array Argument

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Demonstrates how to call a JavaScript function with an argument that is an array. Delphi ActiveX

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());

JavaScript

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;
}