Installation error with the 'legacy' branch

[call-me-anything-you-want]

Hi, I'm trying to use the 'legacy' branch of this repo to visualize the agents trained using the code in the 'neurips2019' branch of 'human_aware_rl' (this)
However, when I'm following the installation instructions in README, I got some errors.
The errors were raised when I'm trying to run npm run build.

/home/pc/overcooked-demo/static/js/demo/index.js:1
import $ from "jquery";
^
ParseError: 'import' and 'export' may appear only with 'sourceType: module'

/home/pc/overcooked-demo/static/js/demo/replay-index.js:1
import $ from "jquery";
^
ParseError: 'import' and 'export' may appear only with 'sourceType: module'

Any idea how to solve this?