the demo does not work

[pikilipita]

The demo linked in the readme (https://harfbuzz.github.io/harfbuzzjs/demo/) does not work, the console error is:

Uncaught (in promise) TypeError: buffer.json is not a function

seen on Firefox and Chrome

[khaledhosny]

I fixed it in the tree. The deployed version will be fixed once we cut a new release.