UPDATE: Resource override importer is now available in Requestly - Documentation
Requestly doesn't support importing configurations from Resource Override at this point. I have created a Github Issue here. Please feel free to contribute directly to the source code or watch the issue.
In the meantime, you can use the following tips to migrate your JS redirects from Resource Override to Requestly.
You need to understand the different operators supported in Requestly. You can find the documentation here - https://docs.requestly.com/general/http-rules/advanced-usage/rule-operators
Exact Match in Resource Override. Resource Override Config
From - http://www.ex.com/neat.js
To - http://local:8080/cool.js
This becomes a very straightforward setup in Requestly. Use the HTTP Redirect Rule with the "Equals" operator.
Request URL "Equals" http://www.ex.com/neat.js
Destination http://local:8080/cool.js
Wildcard Match in "Match URL". Resource Override Config
Match URL - http://www.ex.com/*.js
Replace URL - http://local:8080/*.js
In Requestly, Use the "Wildcard" operator and the substituted value should be replaced with $1,$2, etc.
e.g. In Requestly, You will use HTTP Redirect Rule like
URL "Matches Wildcard" http://www.ex.com/*.js
Destination URL - http://local:8080/$1.js
Multiple Wildcard Operators. Resource Override Config
Match URL - http://ex.com/*/**/***.js
Replace URL - http://local:8080/**/*/***.js
In Requestly, This becomes HTTP Redirect Rule with Wildcard Operator like.
Request URL "Matches Wildcard" http://ex.com/*/*/*.js
Destination URL http://local:8080/$2/$1/$3.js
If you end up building a script for this, feel free to open a PR and contribute to the requestly repo.