How to output from function to log file

As I am working on it more I realized using Write-Host, as I am, pushes the output of my functions to the current host.  I need to find a way to pass the host output to the file.  Sometimes it works, sometimes it doesn't and I'm not sure what determines which.  I'll try outputting directly to the file, but, I believe I tried this and it didn't work.

Can you explain more on "it didn't work"? the output is not written to the log file as expected? if so, can you share the code where the output failed at?

I am trying to build some functions that create/validate folders.  Here is the code:

function Create-Folder{
param(
[parameter(Mandatory=$true)]
[string]
$folderPath,
[parameter(Mandatory=$true)]
[string]
$folderName
)

# Set folder context
cd $folderPath;

# Combine folderPath and folderName.
$folder = "$folderPath\$folderName";

# Check to see if folder already exists
if([System.IO.Directory]::Exists($folder))
{
# Notify host folder already exists.
Write-Output "$(Time-Stamp): $folder already exists.";
}
else
{
# Attempt to create folder.
Try
{
# Notify host of folder creation
Write-Output "$(Time-Stamp): Creating folder: $folder.";

# Create folder
$folderStatus = New-Item -Path $folder -ItemType Directory;
}
# Catch exceptions
Catch [System.Exception]
{
# Notify host of exception
Write-Output "$(Time-Stamp): Error creating folder $folder.";
}
Finally
{
# Validate folder was created
Write-Output "$(Time-Stamp): Validating folder: $folder.";
if([System.IO.Directory]::Exists($folder))
{
Write-Output "$(Time-Stamp): $folder was created.";
}
else
{
Write-Output "$(Time-Stamp): $folder was not created.";
}
}
}
}

function Time-Stamp{

#################################################
#
# NOTE: This function returns a DateTime for Now as a string.
#
# USAGE: Time-Stamp
#
#################################################

return [System.DateTime]::Now.ToString("yyyy.MM.dd hh:mm:ss");
}

When I call the Create-Folder function it writes to the host instead of to the file specified in the | out-file call. It would look like this:

Create-Folder C:\folderpath foldername | Out-file -path C:\log.txt -Encoding ASCII -Append

I have this updated script:

function Log-Script
{
	param(
		[Parameter(ValueFromPipeline=$true,Mandatory=$false)]
		[string]
		$logFilePath
	)
	
	if(!$logFilePath)
	{
		$_ | %{Out-Host -InputObject $_};
	}
	else
	{
		$_ | %{Out-Host -InputObject $_; Out-File -InputObject $_ -FilePath $logFilePath -Encoding ASCII -Append}
	}
}

When I run the command below without the function code wrapped around it works fine.

dir | %{Out-Host -InputObject $_; Out-File -InputObject $_ -FilePath $logFilePath -Encoding ASCII -Append}

Log-Script : The input object cannot be bound to any parameters for the command either because the command does not take pip
eline input or the input and its properties do not match any of the parameters that take pipeline input.
At line:1 char:16
+ dir |Log-Script <<<<  
    + CategoryInfo          : InvalidArgument: (windowspowershell:PSObject) [Log-Script], ParameterBindingException
    + FullyQualifiedErrorId : InputObjectNotBound,Log-Script

Can you please post the solution to this? That link is dead.

This worked for me. 

Function OutFile{
Param([Parameter(ValueFromPipeline=$True)] $message)
$message | Out-File -FilePath $script:LogPath -Append
}