Visual FoxPro

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. Visual FoxPro

LOCAL lnSuccess
LOCAL loSbScript
LOCAL loJs
LOCAL loResult
LOCAL loFuncCall
LOCAL loArgsArray
LOCAL loArg
LOCAL loSbOut

lnSuccess = 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;
* }

loSbScript = CreateObject('Chilkat.StringBuilder')
lnSuccess = loSbScript.LoadFile("js_function_array_arg.js","utf-8")
IF (lnSuccess = 0) THEN
    ? loSbScript.LastErrorText
    RELEASE loSbScript
    CANCEL
ENDIF

loJs = CreateObject('Chilkat.Js')

loResult = CreateObject('Chilkat.JsonObject')
loResult.EmitCompact = 0

* Call Eval to add the function to the context's global object
lnSuccess = loJs.Eval(loSbScript,loResult)
IF (lnSuccess = 0) THEN
    * Examine the result for an exception.
    ? loResult.Emit()

    * Also examine the LastErrorText.
    ? loJs.LastErrorText
    RELEASE loSbScript
    RELEASE loJs
    RELEASE loResult
    CANCEL
ENDIF

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

loFuncCall = CreateObject('Chilkat.JsonObject')
loFuncCall.EmitCompact = 0

* 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('Chilkat.JsonArray')

* The 1st argument in the arguments array is itself an array.
* Passing -1 indicates to append to the array.
loArg = CreateObject('Chilkat.JsonArray')
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
*     ]
*   ]
* }

lnSuccess = loJs.CallFunction(loFuncCall,loResult)
IF (lnSuccess = 0) 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
    CANCEL
ENDIF

? loResult.Emit()

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

* The function also emitted text to the console.

loSbOut = CreateObject('Chilkat.StringBuilder')
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