TL;DR

Solid 2.0 beta is now available, fundamentally changing how reactivity, async operations, and state management work with first-class support for Promises, a new <Loading> component, and optimistic updates via action.

Breaking

• List rendering: Index is replaced with <For keyed={false}> using item() and i() accessors.
• Effects & lifecycle: createEffect is split into compute and apply, and onMount is replaced by onSettled with cleanup capabilities.
• Stores: Setters are now draft-first; use storePath() for previous path-style behavior.
• DOM: use: directives are removed; use ref directive factories instead.

New

• Async Support: Computations can now return Promises, enabling seamless handling of asynchronous data.
• Optimistic Updates: action combined with optimistic primitives simplifies managing UI state during server interactions.
• <Loading> Component: Provides a declarative way to display loading states for initial renders and data revalidation.

Fixes Worth Knowing

None

Before You Upgrade

Review the migration guide at https://github.com/solidjs/solid/blob/next/documentation/solid-2.0/MIGRATION.md before upgrading.

TL;DR

SolidJS now includes improved JSX validation using JSDOM (in-browser DOM implementation) to catch invalid HTML during build time, preventing unexpected browser behavior.

Breaking

• Browser Field Removal: The browser field has been removed from package exports. Legacy packages without export condition support may experience resolution issues.

New

• Advanced Event Handling: Events now support object syntax for setting options like passive or capture directly within the on: directive, replacing deprecated oncapture: syntax.
• Custom Element Support: Improved detection of custom elements using the is attribute and better event handling within shadow DOM.

Fixes Worth Knowing

• Hydration Errors: Hydration mismatch errors now display the problematic template, aiding debugging.
• Lazy Image Handling: Corrected an issue with cloning lazy-loaded images.
• Improved Exports: Client methods are now exported to the server to prevent import errors.

TL;DR

Signals in Solid now only notify components when the value actually changes, improving performance and consistency with standard reactive principles (data reactivity).

Breaking

• Signals no longer always notify on change (prevents unnecessary re-renders).
• createSignal and createMemo comparators now behave differently (may require updating custom comparators).

Before You Upgrade

If you’ve customized signal comparison logic with a comparator or false in createSignal or createMemo, review its behavior to ensure it still meets your needs.