create-emotion

create-emotion

Create distinct instances of emotion.

The main emotion repo can be thought of as a call to createEmotion with sensible defaults for most applications.

import createEmotion from 'create-emotion'

const context = typeof global !== 'undefined' ? global : {}

export const {
  flush,
  hydrate,
  cx,
  merge,
  getRegisteredStyles,
  injectGlobal,
  keyframes,
  css,
  sheet,
  caches
} = createEmotion(context)

Upside

• Calling it directly will allow for some low level customization.

• Create custom names for emotion APIs to help with migration from other, similar libraries.

• Could set custom key to 👩‍🎤, 🥞, ⚛️, 👩‍🎨

Downside

• Introduces some amount of complexity to your application that can vary depending on developer experience.

• Required to keep up with changes in the repo and API at a lower level than if using emotion directly

Primary use cases

• Using emotion in embedded contexts such as an <iframe/>

• Setting a nonce on any <style/> tag emotion creates for security purposes

• Use emotion with a developer defined <style/> tag

• Using emotion with custom stylis plugins

Advanced use cases

• Using emotion in component libraries to sync up multiple intances of emotion together

import createEmotion from 'create-emotion'

const context = typeof global !== 'undefined' ? global : {}

export const {
  flush,
  hydrate,
  cx,
  merge,
  getRegisteredStyles,
  injectGlobal,
  keyframes,
  css,
  sheet,
  caches
} = createEmotion(context)

create-emotion accepts a context and a set of options.

Context

emotion requires a global object for server-side rendering to ensure that even if a module is calling an emotion instance from two paths(e.g. the same emotion instance in multiple node_modules, this can happen often with linking #349) they'll still both work with SSR. If you aren't using SSR, context can be an empty object. This isn't required in the browser because your bundler should deduplicate modules.

Multiple instances in a single app example

import createEmotion from 'create-emotion'

const context = typeof global !== 'undefined' ? global : {}

if (context.__MY_EMOTION_INSTANCE__ === undefined) {
  context.__MY_EMOTION_INSTANCE__ = {}
}

export const {
  flush,
  hydrate,
  cx,
  merge,
  getRegisteredStyles,
  injectGlobal,
  keyframes,
  css,
  sheet,
  caches
} = createEmotion(context.__MY_EMOTION_INSTANCE__, {
  // The key option is required when there will be multiple instances in a single app
  key: 'some-key'
})

Note: calling createEmotion twice with the same context will use the same instance, so options provided in another call of createEmotion with the same context will be ignored.

Options

nonce: string

A nonce that will be set on each style tag that emotion inserts for Content Security Policies.

stylisPlugins: Function | Array

A Stylis plugin or plugins that will be run by stylis during preprocessing. Read Stylis' docs to find out more. This can for be used for many purposes such as RTL.

prefix: boolean | Function

Allows changing Stylis' prefixing settings, this defaults to true. It can be a boolean or a function to dynamicly set which properties are prefixed. More information can be found in Stylis' docs

key: string

The prefix before class names, this defaults to css. It will also be set as the value of the data-emotion attribute on the style tags that emotion inserts and it's used in the attribute name that marks style elements in renderStylesToString and renderStylesToNodeStream. This is required if using multiple emotion instances in the same app.

container: HTMLElement

A DOM Node that emotion will insert all of it's style tags into, this is useful for inserting styles into iframes.