core: generic error handling

[dsebastien]

Goal: clarify how errors should be handled on the client side and provide some generic/reusable error handling mechanisms (routing errors, unhandled exceptions, ...).

Provide some documentation about generic error handling.

Cases to consider:

1) interactions with the back-end and errors:

• timeouts
• 4xx error codes & how to map error(s) with the UI?
• 5xx error codes

2) best practices for defensive programming on the front-end

• try/catch
• logging
• ? 3) describe reusable coding patterns 4) how to visualize errors: useful information on the UI for users and useful detailed information in debug logs

For the dev guide:

• error handling utilities provided by Stark
• code design for handling errors: try-catch, promises & observables, retry & bail-out, how to handle errors returned by the back-end, ...
• how to display errors (notifications, message pane, ...)

Tasks:

• [ ] review and complete list of cases to cover
• [ ] design solution(s)
• [ ] implement
• [ ] add to developer guide

[dsebastien]

Some old (NG1) links:

• https://github.com/johnpapa/ng-demos/blob/master/modular/src/client/app/blocks/router/routehelper.js
• https://github.com/johnpapa/ng-demos/blob/master/modular/src/client/app/blocks/exception/exception.js
• https://github.com/johnpapa/ng-demos/blob/master/modular/src/client/app/blocks/exception/exception-handler.provider.js
• http://www.2ality.com/2016/04/unhandled-rejections.html

[dsebastien]

https://medium.com/@siddhartha.ng/angular-2-error-handling-99575c546b21