Will Lightning Web Components have retrocompatibility?
Having played a little with lightning web component during pilot, I think yes sooner or later everyone will be using lightning web components to build their apps. To begin with currently what i know is it lacks support for communities or flows and many other areas (Official docs are yet to be released so we will come more when docs go out on 17th Dec). However eventually (may be an year from now ) I think Salesforce will make every attempt to add the support lwc everywhere with time.
Why I think LWC is future?
Excellent ES6 and beyond Javascript support.
Faster rendering performance.
Consistent with the webcomponent framework specifications from w3 (https://www.w3.org/standards/techs/components#w3c_all)
Excellent tooling support .(Salesforce built great tooling utility - https://marketplace.visualstudio.com/items?itemName=salesforce.salesforcedx-vscode-lwc)
The syntax and semantics looks to be very clear and adheres to the current webcomponents standards.
Current State Of Aura
- Still supported by salesforce and going to be supported
- Salesforce looks to have great documentation (available in spring 19 orgs) on how to use aura with lightning web components as well how to migrate your existing aura components to lightning web components.
I am sure salesforce will support aura for long time as it will take few more years for them to replace everything under the hood(Safe harbor and note that I don't work for salesforce so do not buy in just based on what write or speak).
I think you should support your aura components and keep enhancing them however start the learning path by playing with docs. Since the product will be GA in new year, if you have a new component coming up surely look to build using the LWC.
For existing components take opportunity to ask few questions
- Should I redesign with better UX as a part of lwc migration?
- What were some of the bottlenecks you encountered when building with aura . Does the new framework fill them?
- What your end users want from the components you have. Your release backlog. If you think LWC will fulfill some of these requirements at a greater velocity then I would say just go for it knowing its going to GA so you know you will have access to support on this.
Yes, Aura components will work with LWC. In fact, Salesforce has already internally been using LWC for a year now! All those standard components you've used, like lightning:button, are actually LWC components, and you didn't even notice. Aura will be used for the foreseeable future, as it is still the core base of Lightning Components; it's only the higher-level components that we use every day are written in LWC. An underlying framework is still required. What LWC means is that your components will (eventually) be portable to other platforms, like React, with little or no modification, unlike Aura, which is inherently not compatible with other platforms. The most relevant text is actually from that post itself:
If you are already developing Lightning components with the Aura programming model, you can continue to do so. Your Aura components will continue to work as before. You can build new components with Aura or Lightning Web Components. Your Aura and Lightning Web Components can coexist and interoperate. Over time, you can consider migrating your Aura Components to Lightning Web Components, starting with the components that would benefit the most from the performance benefits of Lightning Web Components.
You can keep using Aura, or you can use LWC, or you can mix-and-match. LWC has better performance characteristics, so you should consider learning and leveraging LWC, but you'll be able to use Aura until such time that you decide to move to LWC.
To add on top of @sfdcfox. You got your answer in the blog itself.
Coexistence and interoperability:
With the addition of Lightning Web Components, there are now two ways(but not the only way!) to build Lightning components:
- Aura Components, leveraging its own component model, templates, and modular development programming model.
- Lightning Web Components, built on top of the web standards breakthroughs of the last five years: web components, custom elements, Shadow DOM, etc.
If you are already developing Lightning components with the Aura programming model, you can continue to do so. Your Aura components will continue to work as before. You can build new components with Aura or Lightning Web Components. Your Aura and Lightning Web Components can coexist and interoperate. Over time, you can consider migrating your Aura Components to Lightning Web Components, starting with the components that would benefit the most from the performance benefits of Lightning Web Components.
Basically you can use the base components and framework specific components as if today, but you can migrate if you want to take benefit of those of lightning web components