matrix-react-sdk

matrix-react-sdk is now actively maintained at element-hq/matrix-react-sdk

This is a react-based SDK for inserting a Matrix chat/voip client into a web page developed from 2015 through 2024 as part of the Matrix.org Foundation.

This package provides the React components needed to build a Matrix web client using React. It is not usable in isolation, and instead must be used from a 'skin'.

The only skin that existed during its development was vector-im/element-web; it and matrix-org/matrix-react-sdk have effectively been considered as a single project (for instance, matrix-react-sdk bugs have been filed against vector-im/element-web rather than this project). For this reason it is now maintained at element-hq/matrix-react-sdk.

See the following blog posts for more information:

• https://matrix.org/blog/2024/08/heart-of-matrix/
• https://element.io/blog/sustainable-licensing-at-element-with-agpl/

Developer Guide

Platform Targets:

• Chrome, Firefox and Safari.
• WebRTC features (VoIP and Video calling) are only available in Chrome & Firefox.
• Mobile Web is not currently a target platform - instead please use the native iOS (https://github.com/matrix-org/matrix-ios-kit) and Android (https://github.com/matrix-org/matrix-android-sdk2) SDKs.

All code lands on the develop branch - master is only used for stable releases. Please file PRs against develop!!

We use the same contribution guide as Element. Check it out here: https://github.com/vector-im/element-web/blob/develop/CONTRIBUTING.md

Our code style is also the same as Element's: https://github.com/vector-im/element-web/blob/develop/code_style.md

Code should be committed as follows:

• All new components: https://github.com/matrix-org/matrix-react-sdk/tree/master/src/components
• Element-specific components: https://github.com/vector-im/element-web/tree/master/src/components
  • In practice, matrix-react-sdk is still evolving so fast that the maintenance burden of customising and overriding these components for Element can seriously impede development. So right now, there should be very few (if any) customisations for Element.
• CSS: https://github.com/matrix-org/matrix-react-sdk/tree/master/res/css
• Theme specific CSS & resources: https://github.com/matrix-org/matrix-react-sdk/tree/master/res/themes

React components in matrix-react-sdk come in two different flavours: 'structures' and 'views'. Structures are stateful components which handle the more complicated business logic of the app, delegating their actual presentation rendering to stateless 'view' components. For instance, the RoomView component that orchestrates the act of visualising the contents of a given Matrix chat room tracks lots of state for its child components which it passes into them for visual rendering via props.

Good separation between the components is maintained by adopting various best practices that anyone working with the SDK needs to be aware of and uphold:

• Components are named with upper camel case (e.g. views/rooms/EventTile.js)

• They are organised in a typically two-level hierarchy - first whether the component is a view or a structure, and then a broad functional grouping (e.g. 'rooms' here)

• The view's CSS file MUST have the same name (e.g. view/rooms/MessageTile.css). CSS for matrix-react-sdk currently resides in https://github.com/matrix-org/matrix-react-sdk/tree/master/res/css.

• Per-view CSS is optional - it could choose to inherit all its styling from the context of the rest of the app, although this is unusual for any but

• Theme specific CSS & resources: https://github.com/matrix-org/matrix-react-sdk/tree/master/res/themes structural components (lacking presentation logic) and the simplest view components.

• The view MUST only refer to the CSS rules defined in its own CSS file. 'Stealing' styling information from other components (including parents) is not cool, as it breaks the independence of the components.

• CSS classes are named with an app-specific name-spacing prefix to try to avoid CSS collisions. The base skin shipped by Matrix.org with the matrix-react-sdk uses the naming prefix "mx*". A company called Yoyodyne Inc might use a prefix like "yy*" for its app-specific classes.

• CSS classes use upper camel case when they describe React components - e.g. .mx_MessageTile is the selector for the CSS applied to a MessageTile view.

• CSS classes for DOM elements within a view which aren't components are named by appending a lower camel case identifier to the view's class name - e.g. .mx_MessageTile_randomDiv is how you'd name the class of an arbitrary div within the MessageTile view.

• We deliberately use vanilla CSS 3.0 to avoid adding any more magic dependencies into the mix than we already have. App developers are welcome to use whatever floats their boat however. In future we'll start using css-next to pull in features like CSS variable support.

• The CSS for a component can override the rules for child components. For instance, .mxRoomList .mx_RoomTile {} would be the selector to override styles of RoomTiles when viewed in the context of a RoomList view. Overrides _must be scoped to the View's CSS class - i.e. don't just define .mx_RoomTile {} in RoomList.css - only RoomTile.css is allowed to define its own CSS. Instead, say .mx_RoomList .mx_RoomTile {} to scope the override only to the context of RoomList views. N.B. overrides should be relatively rare as in general CSS inheritance should be enough.

• Components should render only within the bounding box of their outermost DOM element. Page-absolute positioning and negative CSS margins and similar are generally not cool and stop the component from being reused easily in different places.

Originally matrix-react-sdk followed the Atomic design pattern as per http://patternlab.io to try to encourage a modular architecture. However, we found that the grouping of components into atoms/molecules/organisms made them harder to find relative to a functional split, and didn't emphasise the distinction between 'structural' and 'view' components, so we backed away from it.

Github Issues

All issues should be filed under https://github.com/vector-im/element-web/issues for now.

Development

Ensure you have the latest LTS version of Node.js installed.

Using yarn instead of npm is recommended. Please see the Yarn 1 install guide if you do not have it already. This project has not yet been migrated to Yarn 2, so please ensure yarn --version shows a version from the 1.x series.

matrix-react-sdk depends on matrix-js-sdk. To make use of changes in the latter and to ensure tests run against the develop branch of matrix-js-sdk, you should set up matrix-js-sdk:

git clone https://github.com/matrix-org/matrix-js-sdk
cd matrix-js-sdk
git checkout develop
yarn link
yarn install

Then check out matrix-react-sdk and pull in dependencies:

git clone https://github.com/matrix-org/matrix-react-sdk
cd matrix-react-sdk
git checkout develop
yarn link matrix-js-sdk
yarn install

See the help for yarn link for more details about this.

Running tests

Ensure you've followed the above development instructions and then:

yarn test

Running lint

To check your code complies with the project style, ensure you've followed the above development instructions and then:

yarn lint

Dependency problems

If you see errors (particularly "Cannot find module") running the lint or test commands, and yarn install doesn't fix them, it may be because yarn is not fetching git dependencies eagerly enough.

Try running this:

yarn cache clean && yarn install --force

Now the yarn commands should work as normal.

End-to-End tests

We use Playwright and Element Web for end-to-end tests. See docs/playwright.md for more information.