Intellij auto-import does not work for some packages.
e.g. here is a simple example project on Github where the auto-import from the change-case package does not work:
change-case
package has type defs in the subdirs dist
and dist.es2015
Auto-import only works for packages added as direct dependencies. Adding "snake-case": "^3.0.3"
to package.json
should help: