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Consuming EUI

What's available

EUI publishes React UI components, JavaScript helpers called services, and utilities for writing Jest tests. Please refer to the Elastic UI Framework website for comprehensive info on what's available.

EUI is published through NPM as a dependency. We also provide a starter projects for:

Components

You can import React components from the top-level EUI module.

import {
  EuiButton,
  EuiCallOut,
  EuiPanel,
} from '@elastic/eui';

Services

Most services are published from the lib/services directory. Some are published from their module directories in this directory.

import { keys } from '@elastic/eui/lib/services';
import { Timer } from '@elastic/eui/lib/services/time';

Test

Test utilities are published from the lib/test directory.

import { findTestSubject } from '@elastic/eui/lib/test';

Requirements and dependencies

EUI expects that you polyfill ES2015 features, e.g. babel-polyfill. Without an ES2015 polyfill your app might throw errors on certain browsers.

EUI also has moment and @elastic/datemath as dependencies itself. These are already loaded in most Elastic repos, but make sure to install them if you are starting from scratch.

Using EUI in Kibana

The EUI CSS is included in Kibana's CSS bundle. To use EUI code in Kibana, simply import the components and services you want.

Using EUI in a standalone project

You can consume EUI in standalone projects, such as plugins and prototypes.

Importing CSS or SCSS

Most of the time, you just need the CSS, which provides the styling for the React components. In this case, you can use Webpack to import the compiled EUI CSS with the style,css, and postcss loaders.

import '@elastic/eui/dist/eui_theme_light.css';

If you want access to the Sass variables, functions, and mixins in EUI then you'll need to import the SCSS file. This will require style, css, postcss, and sass loaders. You'll also want to import the SCSS file into one of your own SCSS files, to gain access to these variables, functions, and mixins.

// index.scss
@import '../node_modules/@elastic/eui/src/theme_light.scss';

By default, EUI ships with a font stack that includes some outside, open source fonts. If your system is internet available you can include these by adding the following imports to your SCSS/CSS files, otherwise you'll need to bundle the physical fonts in your build. EUI will drop to System Fonts (which you may prefer) in their absence.

// index.scss
@import url('https://fonts.googleapis.com/css?family=Roboto+Mono:400,400i,700,700i');
@import url('https://rsms.me/inter/inter-ui.css');

Reusing the variables in JavaScript

The Sass variables are also made available for consumption as json files. This enables reuse of values in css-in-js systems like styled-components. As the following example shows, it can also make the downstream components theme-aware without much extra effort:

import * as React from 'react';
import * as ReactDOM from 'react-dom';
import styled, { ThemeProvider } from 'styled-components';
import * as euiVars from '@elastic/eui/dist/eui_theme_light.json';

const CustomComponent = styled.div`
  color: ${props => props.theme.euiColorPrimary};
  border: ${props => props.theme.euiBorderThin};
`;

ReactDOM.render(
  <ThemeProvider theme={euiVars}>
    <CustomComponent>content</CustomComponent>
  </ThemeProvider>
, document.querySelector('#renderTarget'));

"Module build failed" or "Module parse failed: Unexpected token" error

If you get an error when importing a React component, you might need to configure Webpack's resolve.mainFields to ['webpack', 'browser', 'main'] to import the components from lib instead of src. See the Webpack docs for more info.

Failing icon imports

To reduce EUI's impact to application bundle sizes, the icons are dynamically imported on-demand. This is problematic for some bundlers and/or deployments, so a method exists to preload specific icons an application needs.

import { appendIconComponentCache } from '@elastic/eui/es/components/icon/icon';

import { icon as EuiIconArrowDown } from '@elastic/eui/es/components/icon/assets/arrow_down';
import { icon as EuiIconArrowLeft } from '@elastic/eui/es/components/icon/assets/arrow_left';

// One or more icons are passed in as an object of iconKey (string): IconComponent
appendIconComponentCache({
  arrowDown: EuiIconArrowDown,
  arrowLeft: EuiIconArrowLeft,
});

Customizing with className

We do not recommend customizing EUI components by applying styles directly to EUI classes, eg. .euiButton. All components allow you to pass a custom className prop directly to the component which will then append this to the class list. Utilizing the cascade feature of CSS, you can then customize by overriding styles so long as your styles are imported after the EUI import.

<EuiButton className="myCustomClass__button" />

// Renders as:

<button class="euiButton myCustomClass__button" />

Using the test-env build

EUI provides a separate babel-transformed and partially mocked commonjs build for testing environments in consuming projects. The output is identical to that of lib/, but has transformed async functions and dynamic import statements, and also applies some useful mocks. This build mainly targets Kibana's Jest environment, but may be helpful for testing environments in other projects.

Mapping to the test-env directory

In Kibana's Jest configuration, the moduleNameMapper option is used to resolve standard EUI import statements with test-env aliases.

moduleNameMapper: {
  '@elastic/eui$': '<rootDir>/node_modules/@elastic/eui/test-env'
}

This eliminates the need to polyfill or transform the EUI build for an environment that otherwise has no need for such processing.

Mocked component files

Besides babel transforms, the test environment build consumes mocked component files of the type src/**/[name].testenv.*. During the build, files of the type src/**/[name].* will be replaced by those with the testenv namespace. The purpose of this mocking is to further mitigate the impacts of time- and import-dependent rendering, and simplify environment output such as test snapshots. Information on creating mock component files can be found with testing documentation.