How concatenate files in MSBuild and preserve tabs and spaces

Question

I'm trying to concatenate a few files during my build but the way I tried strips out the tabs and spaces leaving the output unformatted.

<CreateItem Include="Scripts\ApplicationModule.d.ts; Scripts\AccountModule.d.ts; Scripts\FeedModule.d.ts;">
  <Output TaskParameter="Include" ItemName="ApplicationDefinitionFiles" />
</CreateItem>

<ReadLinesFromFile File="%(ApplicationDefinitionFiles.FullPath)">
  <Output TaskParameter="Lines" ItemName="ApplicationDefinitionLines" />
</ReadLinesFromFile>

<WriteLinesToFile File="Scripts\ApplicationDefinition.d.ts" Lines="@(ApplicationDefinitionLines)" Overwrite="true" />

What's the way to preserve formatting?

Answer 1

This is what I ended up with when faced with the same problem:

<Target Name="ConcatenateScripts">
  <!-- List all the files you want to concatenate. -->
  <ItemGroup>
    <ConcatFiles Include="
        Scripts\ApplicationModule.d.ts; 
        Scripts\AccountModule.d.ts;
        Scripts\FeedModule.d.ts;"/>
  </ItemGroup>

  <!-- Read the contents of the files (preserving tabs/spaces). -->
  <ItemGroup>
    <FileContents Include="$([System.IO.File]::ReadAllText(%(ConcatFiles.Identity)))"/>
  </ItemGroup>

  <!-- Write the result to a single file. -->
  <WriteLinesToFile File="Scripts\ApplicationDefinition.d.ts" Lines="@(FileContents)" Overwrite="true" />
</Target>

<!-- Concatenate scripts on AfterBuild. -->
<Target Name="AfterBuild">
  <CallTarget Targets="ConcatenateScripts"/>
</Target>

This is a modified version of this blog post but using $([System.IO.File]::ReadAllText(...) instead of the ReadLinesFromFile task, as suggested in this answer.