I have a Docusaurus project which, when I run locally with npm run build for the first time, takes 727 seconds to build. Once the build folder is already generated, running npm run build takes only 234 seconds. I am trying to implement a similar caching mechanism for my pipeline:

  - name: Cache npm dependencies
    uses: actions/cache@v2
    with:
      path: node_modules
      key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}
      restore-keys: |
        ${{ runner.os }}-node-

  - name: Install Dependencies
    run: npm ci

  - name: Cache build folder
    uses: actions/cache@v2
    with:
      path: build
      key: ${{ runner.os }}-build-${{ hashFiles('**/build/**') }}
      restore-keys: |
        ${{ runner.os }}-build-

  - name: Build Docs
    env:
    run: npm run build

I can see that for the build folder the cache gets restored:

12s
Run actions/cache@v2
Received 0 of 208433371 (0.0%), 0.0 MBs/sec
Received 67108864 of 208433371 (32.2%), 32.0 MBs/sec
Received 167772160 of 208433371 (80.5%), 53.3 MBs/sec
Received 208433371 of 208433371 (100.0%), 56.4 MBs/sec
Cache Size: ~199 MB (208433371 B)
/usr/bin/tar -z -xf /home/runner/work/_temp/270df659-fec8-4690-9d84-17fc24256fd9/cache.tgz -P -C /home/runner/work/myrepo/myrepo
Cache restored successfully
Cache restored from key: Linux-build-c1b2051987189b5de83695a87c9e2ac4ddb50489e21342cbf5eff3829882ed46

However, although it gets restored, the caching doesnt work and the Build Docs stage for both runs takes 20 minutes. How could I overcome this issue?