styled-components/src/constructors/keyframes.js

**This is a work in progress** based off of [this demo](https://github.com/geelen/css-components-demo).

// @flow
import hashStr from 'glamor/lib/hash'
import css from './css'
import GlobalStyle from '../models/GlobalStyle'
import type { Interpolation } from '../types'

const replaceWhitespace = (str: string): string => str.replace(/\s|\\n/g, '')

export default (strings: Array<string>, ...interpolations: Array<Interpolation>): Number => {
  const rules = css(strings, ...interpolations)
  const name = `k${hashStr(replaceWhitespace(JSON.stringify(rules)))}`
  const keyframes = new GlobalStyle(rules, `@keyframes ${name}`)
  keyframes.generateAndInject()
  return name
}