Changelog

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

Changelogs can change! If you spot something is wrong or missing, please consider opening an issue or a pull request to fix it.

Unreleased

Changed

• [lustre/event] Correctly document the unit used for debounce and throttle.
• [lustre/runtime] Fix a bug where holding a WeakRef to a context subscription function would cause it to GC unpredictably.
• [lustre/server_component] Fixed a bug where listening to attribute changes would crash the JavaScript server component runtime.

[v5.3.4] - 2025-08-23

Changed

• [lustre/server_component] Fixed even more bugs in the JavaScript server component runtime.

[v5.3.3] - 2025-08-22

Changed

• [lustre/runtime] Fixed a bug where form submitter was not included when constructing form data for decoding.
• [lustre/server_component] Fixed numerous bugs in the JavaScript server component runtime.

[v5.3.2] - 2025-08-09

Changed

• [lustre/runtime] Fixed a bug where the server component runtime was actually an outdated bundle.

[v5.3.1] - 2025-08-09

Changed

• [lustre/runtime] Fixed a bug where using element.unsafe_raw_html would not correctly create the DOM node.

[v5.3.0] - 2025-08-08

Added

• [lustre/component] Added a delegates_focus config option to control how focus is handled in components.
• [lustre/component] Added a on_context_change config option to listen for changes in a parent’s provided context.
• [lustre/component] Added a parts attribute for toggling independent CSS parts in component elements.
• [lustre/effect] Added a provide effect for providing context values to components.
• [lustre/element/svg] Add the svg.namespace constant.
• [lustre/element/svg] Add missing svg.filter, and svg.view elements.

Changed

• [lustre] Fixed a bug where the internal isLustreNode function would incorrectly identify nodes as Lustre nodes when they were not in some cases.
• [lustre/component] Fixed a bug where removing an attribute a component was listening to would cause a runtime error.
• [lustre/component] Fixed a bug where a component’s Shadow Root was incorrectly closed by default.
• [lustre/element] Fixed a bug where a top-level fragment would not be hydrated correctly.
• [lustre/element/keyed] Fixed a bug where keyed elements were not virtualised correctly.
• [lustre/event] Fixed a bug where debounced events of child elements would still fire after the node was removed.
• [lustre/event] Fixed a bug where events would not fire correctly after elements where added to or removed from a preceeding fragment.
• [lustre/runtime] Lustre is now more resilient against other scripts or browser plugins modifying the DOM.
• [lustre/server_component] Fixed a bug where empty value attributes would result in a value of undefined
• [lustre/server_component] Fixed a bug where events inside fragments would not work.

[v5.2.1] - 2025-06-23

Changed

• [lustre/server_component] Fixed a bug where WebSocket connections were initialised twice when the component was mounted.
• [lustre/server_component] Fixed a bug where the event paths sent by the client erroneously included the shadowRoot itself.

[v5.2.0] - 2025-06-23

Added

• [lustre/dev/query] Added a matches function to check if an element matches a given selector.
• [lustre/dev/query] Added a has function to check if an element or its descendants match a given selector.
• [lustre/event] Added an advanced function to create event listeners that can conditionally prevent default actions and stop propagation.
• [lustre/event] Added a handler function to create event handlers to be used with advanced.

Changed

• [lustre] Lustre now requires gleam_erlang version >= 1.0.0 and < 2.0.0.
• [lustre] Lustre now requires gleam_otp version >= 1.0.0 and < 2.0.0.
• [lustre] Fix a bug where events can not send the correct message if the browser or external Javascript moved the element.
• [lustre] Fixed a bug where changing the object passed down as a property would not correctly update the property on the DOM element.

[v5.1.1] - 2025-06-06

Changed

• [lustre/event] Fixed a bug where setting prevent_default on an existing event listener would not remove the passive flag.
• [lustre/event] Fixed a bug where throttle would only work when used in combination with debounce.
• [lustre/event] Fixed a bug where throttle would incorrectly call .preventDefault on all discarded events.
• [lustre/element] Fixed a bug where nested fragments would sometimes not be properly replaced

[v5.1.0] - 2025-05-18

Added

• [lustre/attribute] Added a attribute.default_value function to set the defaultValue property of an input.
• [lustre/attribute] Added multple attributes for working with HTML tables: attribute.abbr, attribute.colspan, attribute.headers, attribute.rowspan, attribute.span, attribute.scope.
• [lustre/dev/query] Created a module for querying a view for test purposes.
• [lustre/dev/simulate] Created a module for simulating a running application for test purposes.
• [lustre/event] Added support for debounce and throttle on the same event, at the same time.

Changed

• [lustre] Change gleam_stdlib constraint to >= 0.60.0 and < 2.0.0.
• [lustre/event] Fixed a bug where updating the delay for debounce or throttle would have no effect.
• [lustre/runtime] Fixed a bug where keyed elements where no fully virtualised.

[5.0.3] - 2025-05-09

Changed

• [lustre/attribute] The width and height functions now set the respective attributes instead of properties.
• [lustre/element] Fixed a bug in element.map where the mapper functions were composed in reversed order.
• [lustre/element/html] Fixed a bug where html.textarea would not always update when the content changes.
• [lustre/server_component] Fixed a bug where server_component.script contained invalid characters.

[5.0.2] - 2025-04-20

Changed

• [lustre/runtime] Fixed a bug where stale app state was used to compute patches, leading to empty diffs.

[5.0.1] - 2025-04-19

Changed

• [lustre/event] Fixed a bug with some internal decoders incorrectly using decode.field instead of decode.subfield.

[5.0.0] - 2025-04-19

Added

• [lustre] Added a send function for sending messages to an app’s runtime.
• [lustre] Defines new Runtime and RuntimeMessage types to model communication with running apps.
• [lustre/attribute] Added many many attributes to lustre/attribute.
• [lustre/attribute] Added style as an alternative way to styles to set a single CSS property.
• [lustre/component] Added a lustre/component module with attributes and effects to access Custom Element features such as slots, parts, and CSS custom states.
• [lustre/component] Component’s can be notified of browser autofill requests using the on_form_autofill configuration option.
• [lustre/component] Component’s can be notified of browser restore requests using the on_form_restore configuration option.
• [lustre/component] Component’s can be notified of form reset events using the on_form_reset configuration option.
• [lustre/component] Component’s can listen to attribute value changes using the on_attribute_change configuration option.
• [lustre/component] Component’s can listen to property value changes using the on_property_change configuration option.
• [lustre/component] Component’s can now be made form-associated custom elements using the form_associated configuration option.
• [lustre/component] Component’s can now control whether their shadow dom is open or closed using the open_shadow_root configuration option.
• [lustre/effect] A new after_paint effect allows you to run an effect after the browser paints.
• [lustre/effect] A new before_paint effect allows you to run an effect before the browser paints.
• [lustre/element] Added a new unsafe_raw_html function allows you to render raw unescaped HTML.
• [lustre/element/keyed] Added a lustre/element/keyed module with convenience functions for common keyed elements.
• [lustre/server_component] Defines a new ClientMessage type to model messages sent from the server to the client.
• [lustre/server_component] Added a TransportMethod type and method attribute to choose between websocket, sse, and http methods for server component clients.
• [lustre/server_component] Adds an element function to more-conveniently create the <lustre-server-component> HTML element.
• [lustre/server_component] Adds a subject function to recover the process.Subject of a server component’s runtime.
• [lustre/server_component] Adds a pid function to recover the process.Pid of a server component’s runtime.
• [lustre/server_component] Adds register_subject and deregister_subject functions for Erlang-based server components.
• [lustre/server_component] Adds register_callback and deregister_callback functions for JavaScript-based server components.

Changed

• [lustre] App constructors such as simple and application now have labelled arguments.
• [lustre] component no longer takes a Dict of attribute change callbacks and now takes a list of configuration options.
• [lustre] start and start_server_component now return the new Runtime type.
• [lustre/attribute] property now requires a Json value instead of any dynamic.Dynamic value.
• [lustre/attribute] style has been renamed to styles.
• [lustre/element] fragment no longer renders a wrapper div around its children.
• [lustre/element] to_string_builder and to_document_string_builder have been renamed to to_string_tree and to_document_string_tree respectively.
• [lustre/event] Event handlers written using on now use the new gleam/dynamic/decode API.
• [lustre/event] The submit event now includes a list for form data entries for processing.
• [lustre/event] prevent_default and stop_propagation are now modifiers of the event attribute itself.
• [lustre/server_component] decode_action has been replaced with runtime_message_decoder.
• [lustre/server_component] encode_patch has been replaced with client_message_to_json.

Removed

• [lustre] The Action, ClientSpa, Patch, and ServerComponent types have been removed from the lustre module.
• [lustre] start_actor has been removed in favour of a unified start_server_component for both targets.
• [lustre/attribute] The on function has been removed in favour of the event.on function.
• [lustre/element] The keyed function has been removed and replaced by a dedicated lustre/element/keyed module.
• [lustre/event] The checked, mouse_position, and value decoders have been removed.
• [lustre/server_component] The deprecated set_selector effect has been removed.
• [lustre/server_component] subscribe and unsubscribe have been removed.
• [lustre/server_component] The data attribute has been removed.