Xojo Plugin

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. Xojo Plugin

Dim success As Boolean
success = False

// 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;
// }

Dim sbScript As New Chilkat.StringBuilder
success = sbScript.LoadFile("js_function_array_arg.js","utf-8")
If (success = False) Then
    System.DebugLog(sbScript.LastErrorText)
    Return
End If

Dim js As New Chilkat.Js

Dim result As New Chilkat.JsonObject
result.EmitCompact = False

// Call Eval to add the function to the context's global object
success = js.Eval(sbScript,result)
If (success = False) Then
    // Examine the result for an exception.
    System.DebugLog(result.Emit())

    // Also examine the LastErrorText.
    System.DebugLog(js.LastErrorText)
    Return
End If

// ------------------------------------------------------------------------------
// Call the function calculateTotal(numbers)

Dim funcCall As New Chilkat.JsonObject
funcCall.EmitCompact = False

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

success = funcCall.UpdateString("name","calculateTotal")

// Create the arguments array.
Dim argsArray As New Chilkat.JsonArray

// The 1st argument in the arguments array is itself an array.
// Passing -1 indicates to append to the array.
Dim arg As New Chilkat.JsonArray
success = argsArray.AddArrayAt2(-1,arg)

// Fill in the values for the 1st argument.
success = arg.AddNumberAt(-1,"10.50")
success = arg.AddNumberAt(-1,"20.00")
success = arg.AddNumberAt(-1,"5.25")

// Add the "args" array to the funcCall.
success = funcCall.AppendArrayCopy("args",argsArray)

System.DebugLog(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,result)
If (success = False) Then
    // Examine the result for an exception.
    System.DebugLog(result.Emit())

    // Also examine the LastErrorText.
    System.DebugLog(js.LastErrorText)
    Return
End If

System.DebugLog(result.Emit())

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

// The function also emitted text to the console.

Dim sbOut As New Chilkat.StringBuilder
js.ConsoleOutputSb sbOut
System.DebugLog(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 
success = funcCall.UpdateString("name","calculateTotal")
success = funcCall.UpdateNumber("args[0][0]","10.50")
success = funcCall.UpdateNumber("args[0][1]","20.00")
success = funcCall.UpdateNumber("args[0][2]","5.25")
System.DebugLog(funcCall.Emit())