Lianja

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. Lianja

llSuccess = .F.

// 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;
// }

loSbScript = createobject("CkStringBuilder")
llSuccess = loSbScript.LoadFile("js_function_array_arg.js","utf-8")
if (llSuccess = .F.) then
    ? loSbScript.LastErrorText
    release loSbScript
    return
endif

loJs = createobject("CkJs")

loResult = createobject("CkJsonObject")
loResult.EmitCompact = .F.

// Call Eval to add the function to the context's global object
llSuccess = loJs.Eval(loSbScript,loResult)
if (llSuccess = .F.) then
    // Examine the result for an exception.
    ? loResult.Emit()

    // Also examine the LastErrorText.
    ? loJs.LastErrorText
    release loSbScript
    release loJs
    release loResult
    return
endif

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

loFuncCall = createobject("CkJsonObject")
loFuncCall.EmitCompact = .F.

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

loFuncCall.UpdateString("name","calculateTotal")

// Create the arguments array.
loArgsArray = createobject("CkJsonArray")

// The 1st argument in the arguments array is itself an array.
// Passing -1 indicates to append to the array.
loArg = createobject("CkJsonArray")
loArgsArray.AddArrayAt2(-1,loArg)

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

// Add the "args" array to the funcCall.
loFuncCall.AppendArrayCopy("args",loArgsArray)

? loFuncCall.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
//     ]
//   ]
// }

llSuccess = loJs.CallFunction(loFuncCall,loResult)
if (llSuccess = .F.) then
    // Examine the result for an exception.
    ? loResult.Emit()

    // Also examine the LastErrorText.
    ? loJs.LastErrorText
    release loSbScript
    release loJs
    release loResult
    release loFuncCall
    release loArgsArray
    release loArg
    return
endif

? loResult.Emit()

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

// The function also emitted text to the console.

loSbOut = createobject("CkStringBuilder")
loJs.ConsoleOutputSb(loSbOut)
? loSbOut.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:

loFuncCall.Clear()
loFuncCall.UpdateString("name","calculateTotal")
loFuncCall.UpdateNumber("args[0][0]","10.50")
loFuncCall.UpdateNumber("args[0][1]","20.00")
loFuncCall.UpdateNumber("args[0][2]","5.25")
? loFuncCall.Emit()


release loSbScript
release loJs
release loResult
release loFuncCall
release loArgsArray
release loArg
release loSbOut