PowerShell

Call a JavaScript Function Passing an Object Argument

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Demonstrates how to call a JavaScript function with an argument that is an object. PowerShell

Add-Type -Path "C:\chilkat\ChilkatDotNet47-x64\ChilkatDotNet47.dll"

$success = $false

# This is the JavaScript function we'll call:

# function describeCar(car) {
# 	console.log(`This is a ${car.year} ${car.make} ${car.model}.`);
# }

$sbScript = New-Object Chilkat.StringBuilder
$sbScript.Append("function describeCar(car) { console.log(`This is a ${car.year} ${car.make} ${car.model}.`); }")

$js = New-Object Chilkat.Js

$result = New-Object Chilkat.JsonObject
$result.EmitCompact = $false

# Call Eval to add the function to the context's global object
$success = $js.Eval($sbScript,$result)
if ($success -eq $false) {
    # Examine the result for an exception.
    $($result.Emit())

    # Also examine the LastErrorText.
    $($js.LastErrorText)
    exit
}

# ------------------------------------------------------------------------------
# Call the function describeCar(car)

$funcCall = New-Object 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 object.

# {
#   "name": "describeCar",
#   "args": [
#     {
#       "make": "Toyota",
#       "model": "Corolla",
#       "year": 2022
#     }
#   ]
# }

$funcCall.UpdateString("name","describeCar")

# Create the JSON object that is the argument.
$arg = New-Object Chilkat.JsonObject
$arg.UpdateString("make","Toyota")
$arg.UpdateString("model","Corolla")
$arg.UpdateInt("year",2022)

# Create the arguments array.
$argsArray = New-Object Chilkat.JsonArray
$argsArray.AddObjectCopyAt(0,$arg)

# Add the "args" array to the funcCall.
$funcCall.AppendArrayCopy("args",$argsArray)

$($funcCall.Emit())

$success = $js.CallFunction($funcCall,$result)
if ($success -eq $false) {
    # Examine the result for an exception.
    $($result.Emit())

    # Also examine the LastErrorText.
    $($js.LastErrorText)
    exit
}

$($result.Emit())

# The describeCar JavaScript function returns nothing. 
# Therefore, the result is "undefined".

# {
#   "type": "undefined",
#   "value": "undefined"
# }

# However, the function emitted text to the console.

$sbOut = New-Object Chilkat.StringBuilder
$js.ConsoleOutputSb($sbOut)
$($sbOut.GetAsString())

# Output:
# This is a 2022 Toyota Corolla.

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

$funcCall.Clear()
$funcCall.UpdateString("name","describeCar")
$funcCall.UpdateString("args[0].make","Toyota")
$funcCall.UpdateString("args[0].model","Corolla")
$funcCall.UpdateInt("args[0].year",2022)
$($funcCall.Emit())