element-web/README.md

matrix-react-sdk
================

This is a react-based SDK for inserting a Matrix chat/voip client into a web page.

This package provides the React components needed to build a Matrix web client
using React.  It is not useable in isolation, and instead must be used from
a 'skin'. A skin provides:
 * Customised implementations of presentation components.
 * Custom CSS
 * The containing application
 * Zero or more 'modules' containing non-UI functionality

As of Aug 2018, the only skin that exists is `vector-im/element-web`; it and
`matrix-org/matrix-react-sdk` should effectively
be considered as a single project (for instance, matrix-react-sdk bugs
are currently filed against vector-im/element-web rather than this project).

Translation Status
==================
[![Translation status](https://translate.element.io/widgets/element-web/-/multi-auto.svg)](https://translate.element.io/engage/element-web/?utm_source=widget)

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`!!**

Please follow the standard Matrix contributor's guide:
https://github.com/matrix-org/matrix-js-sdk/blob/develop/CONTRIBUTING.md

Please follow the Matrix JS/React code style as per:
https://github.com/matrix-org/matrix-react-sdk/blob/master/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 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)

  * After creating a new component you must run `yarn reskindex` to regenerate
    the `component-index.js` for the SDK (used in future for skinning)
    <!-- TODO: Remove this once this approach to skinning is replaced -->

  * 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/vector-im/element-web/tree/master/src/skins/vector/css/matrix-react-sdk.

  * 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, .mx_RoomList .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](https://classic.yarnpkg.com/docs/install) 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`:

```bash
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:

```bash
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`](https://classic.yarnpkg.com/docs/cli/link) for
more details about this.

Running tests
=============

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

```bash
yarn test
```

## End-to-End tests

Make sure you've got your Element development server running (by doing `yarn start` in element-web), and then in this project, run `yarn run e2etests`.
See `test/end-to-end-tests/README.md` for more information.