Programmatic Webpack & Jest (ESM): can’t resolve module without ‘.js’ file extension

Ok so I found the solution here.

Basically, had to add 2 things to the webpack config under module.rules:

{
  test: /\.m?js/,
  type: "javascript/auto",
},
{
  test: /\.m?js/,
  resolve: {
    fullySpecified: false,
  },
},