How can I not gitignore in a Github Action?

Sorry for the poor wording in the title. Essentially, I have a website with Typescript (not Node) that I want to host via Github Pages. I have a tsconfig.json that essentially looks like this:

{
	"compilerOptions": {
		"rootDir": "./src",
		"outDir": "./js"
	},

	"include": ["./src"]
}

I don't want my compiled code on the main branch, so my gitignore contains

js/

In order to have my project work on Github Pages, I set up action-build-typescript to compile my Typescript onto a separate branch, which would be the source for Github pages.

on:
  push:
  workflow_dispatch:

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
    - name: Checkout project
      uses: actions/checkout@v3
    - name: Build and push
      uses: alexthemaster/action-build-typescript@master
      with:
        pushToBranch: true
        branch: "gh-pages"
        githubToken: ${{ secrets.GITHUB_TOKEN }}

This works great, however the js/ directory wasn't being created. Some digging revealed that when this action was pushing to the gh-pages branch, the .gitignore was still being applied, thus my Javascript wasn't being committed.

Is there a better way I can do this? Should I just push my compiled code to main?

If you add a commit to the gh-pages branch that removes (or comments out) this line in the .gitignore file, the files will be added in commits on this branch.

Perhaps you have to checkout the gh-pages branch and merge from the source branch first, so that the .gitignore file from the gh-pages branch is used for the commit.

Alternative:
Remove the line from the .gitignore file before the build and push step. To achieve this, you can just overwrite it with a prepared .gitignore-pages file in your source branch. The changed .gitignore file will be committed to the gh-pages branch, but since you probably will never merge ist back to your source branch, this will be no problem.