Doc update: include "Usage with esm"

- Closes #99

README.md

@@ -160,6 +160,14 @@ Unfortunately, `module-alias` itself would not work from Jest due to a custom be
 
 More details on the [official documentation](https://jestjs.io/docs/en/configuration#modulenamemapper-objectstring-string).
 
+## Usage with esm
+
+[esm](https://www.npmjs.com/package/esm) tries to handle all imports when parsing a file, before actually loading any module. This means module-alias' `register` call will not be processed in time. To make `module-alias` work with `esm`, please consider using:
+
+```
+node -r module-alias/register -r esm index.js
+```
+
 ## Known incompatibilities
 
 This module does not play well with: