element-web/packages/shared-components

@element-hq/web-shared-components

Shared React components library for Element Web, Aurora, Element modules... This package provides opinionated UI components built on top of the Compound Design System and Compound Web. This is not a design system by itself, but rather a set of larger components.

Installation in a new project

When adding this library to a new project, as well as installing @element-hq/web-shared-components as normal, you will also need to add compound-web as a peer dependency:

yarn add @element-hq/web-shared-components
yarn add @vector-im/compound-web

(This avoids problems where we end up with different versions of compound-web in the top-level project and web-shared-components).

Usage

Basic Import

Both JavaScript and CSS can be imported as follows:

import { RoomListHeaderView, useViewModel } from "@element-hq/web-shared-components";
import "@element-hq/web-shared-components/dist/element-web-shared-components.css";

or in CSS file:

@import url("@element-hq/web-shared-components");

Using Components

There are two kinds of components in this library:

• regular react component which doesn't follow specific pattern.
• view component(MVVM pattern).

Tip

These components are available in the project storybook.

Regular Components

These components can be used directly by passing props. Example:

import { Flex } from "@element-hq/web-shared-components";
function MyApp() {
    return <Flex align="center" />;
}

View (MVVM) Components

These components follow the MVVM pattern. A ViewModel instance should be provided as a prop.

Here's a basic example:

import { ViewExample } from "@element-hq/web-shared-components";

function MyApp() {
    const viewModel = new ViewModelExample();
    return <ViewExample vm={viewModel} />;
}

Utilities

Internationalization

• useI18n() - Hook for translations
• I18nApi - Internationalization API utilities

Date & Time

• DateUtils - Date formatting and manipulation
• humanize - Human-readable time formatting

Formatting

• FormattingUtils - Text and data formatting utilities
• numbers - Number formatting utilities

Development

Prerequisites

• Node.js >= 20.0.0
• Yarn 1.22.22+

Setup

# Install dependencies
yarn install

# Build the library
yarn prepare

Running Storybook

yarn storybook

Write components

Most components should be written as MVVM pattern view components. See existing components for examples. The exceptions are low level components that don't need a view model.

Write Storybook Stories

All components should have accompanying Storybook stories for documentation and visual testing. Stories are written in TypeScript using the Component Story Format (CSF).

Story File Structure

Place the story file next to the component with the .stories.tsx extension:

MyComponent/
├── MyComponent.tsx
├── MyComponent.module.css
└── MyComponent.stories.tsx

Regular Component Stories

For regular React components (non-MVVM), create stories by defining a meta object and story variations:

import type { Meta, StoryObj } from "@storybook/react-vite";
import { fn } from "storybook/test";
import { MyComponent } from "./MyComponent";

const meta = {
    title: "Category/MyComponent",
    component: MyComponent,
    tags: ["autodocs"],
    args: {
        // Default args for all stories
        label: "Default Label",
        onClick: fn(), // Mock function for tracking interactions
    },
} satisfies Meta<typeof MyComponent>;

export default meta;
type Story = StoryObj<typeof meta>;

// Default story uses the default args
export const Default: Story = {};

// Override specific args for variations
export const WithCustomLabel: Story = {
    args: {
        label: "Custom Label",
    },
};

export const Disabled: Story = {
    args: {
        disabled: true,
    },
};

MVVM Component Stories

For MVVM components, create a wrapper component that uses useMockedViewModel:

import React, { type JSX } from "react";
import { fn } from "storybook/test";
import type { Meta, StoryFn } from "@storybook/react-vite";
import { MyComponentView, type MyComponentViewSnapshot, type MyComponentViewActions } from "./MyComponentView";
import { useMockedViewModel } from "../../useMockedViewModel";

// Combine snapshot and actions for easier typing
type MyComponentProps = MyComponentViewSnapshot & MyComponentViewActions;

// Wrapper component that creates a mocked ViewModel
const MyComponentViewWrapper = ({ onAction, ...rest }: MyComponentProps): JSX.Element => {
    const vm = useMockedViewModel(rest, {
        onAction,
    });
    return <MyComponentView vm={vm} />;
};

export default {
    title: "Category/MyComponentView",
    component: MyComponentViewWrapper,
    tags: ["autodocs"],
    args: {
        // Snapshot properties (state)
        title: "Default Title",
        isLoading: false,
        // Action properties (callbacks)
        onAction: fn(),
    },
} as Meta<typeof MyComponentViewWrapper>;

const Template: StoryFn<typeof MyComponentViewWrapper> = (args) => <MyComponentViewWrapper {...args} />;

export const Default = Template.bind({});

export const Loading = Template.bind({});
Loading.args = {
    isLoading: true,
};

Thanks to this approach, we can directly use primitives in the story arguments instead of a view model object.

Linking Figma Designs

This package uses @storybook/addon-designs to embed Figma designs directly in Storybook. This helps developers compare their implementation with the design specs.

1. Get the Figma URL: Open your design in Figma, click "Share" → "Copy link"
2. Add to story parameters: Include the design object in the meta's parameters
3. Supported URL formats:
   • File links: https://www.figma.com/file/...
   • Design links: https://www.figma.com/design/...
   • Specific node: https://www.figma.com/design/...?node-id=123-456

Example with Figma integration:

export default {
    title: "Room List/RoomListSearchView",
    component: RoomListSearchViewWrapper,
    tags: ["autodocs"],
    args: {
        // ... your args
    },
    parameters: {
        design: {
            type: "figma",
            url: "https://www.figma.com/design/vlmt46QDdE4dgXDiyBJXqp/ER-33-Left-Panel?node-id=98-1979",
        },
    },
} as Meta<typeof RoomListSearchViewWrapper>;

The Figma design will appear in the "Design" tab in Storybook.

Tests

Two types of tests are available: unit tests and visual regression tests.

Unit Tests

These tests cover the logic of the components and utilities. Built with Vitest and React Testing Library.

yarn test:unit

Visual Regression Tests

These tests ensure the UI components render correctly. Built with Storybook and run under vitest using playwright.

yarn test:storybook:update

Each story will be rendered and a screenshot will be taken and compared to the existing baseline. If there are visual changes or AXE violation, the test will fail.

Translations

First see our translation guide and translation dev guide. To generate translation strings for this package, run:

yarn i18n