@try/@catch operator.

Proposal:

Add a try/catch operator to sass to handle @error directives more cleanly without hard compiler crashes.

Use Case

As a developer, I’d like to be able to write test code to cover my sass functions. I’m unable to test all branches of my code as my node-sass compiler crashes if it reaches an @error directive. While I am glad that the @error worked as intended and crashed while I was using the function, I’d like to be able to catch the exception during “test” mode and make an assertion about the message that was thrown.

See: https://github.com/oddbird/true/issues/92 for an example.

Side comments

With sass as popular as it is, and new sass code being written every day, I find that the number of projects that I’ve worked on without tests for functional code to be high. Testing is necessary for maintenance and confidence in code. As sass is becoming a de-facto “language” for writing stylesheets, it seems that the @error operator necessitates a partnering try/catch directive. Even if @error is a weakly typed error, and try/catch doesn’t have exception types, having the ability to catch an exception and handle it (if only for testing purposes) allows me to be confident that the code that I write is working the way I intend.

[mirisuzanne]

This is still planned, and is my next priority once we ship the new color spaces.

[mirisuzanne]

I started on the proposal there, and then got pulled to other things. Happy for feedback or contributions as people have time.