171 lines
4.5 KiB
TypeScript
171 lines
4.5 KiB
TypeScript
import React from 'react'
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import withSideEffect from './side-effect'
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import { AmpStateContext } from './amp-context'
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import { HeadManagerContext } from './head-manager-context'
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import { isInAmpMode } from './amp'
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type WithInAmpMode = {
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inAmpMode?: boolean
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}
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export function defaultHead(inAmpMode = false): JSX.Element[] {
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const head = [<meta charSet="utf-8" />]
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if (!inAmpMode) {
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head.push(<meta name="viewport" content="width=device-width" />)
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}
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return head
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}
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function onlyReactElement(
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list: Array<React.ReactElement<any>>,
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child: React.ReactChild
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): Array<React.ReactElement<any>> {
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// React children can be "string" or "number" in this case we ignore them for backwards compat
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if (typeof child === 'string' || typeof child === 'number') {
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return list
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}
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// Adds support for React.Fragment
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if (child.type === React.Fragment) {
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return list.concat(
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React.Children.toArray(child.props.children).reduce(
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(
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fragmentList: Array<React.ReactElement<any>>,
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fragmentChild: React.ReactChild
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): Array<React.ReactElement<any>> => {
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if (
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typeof fragmentChild === 'string' ||
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typeof fragmentChild === 'number'
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) {
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return fragmentList
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}
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return fragmentList.concat(fragmentChild)
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},
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[]
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)
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)
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}
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return list.concat(child)
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}
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const METATYPES = ['name', 'httpEquiv', 'charSet', 'itemProp']
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/*
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returns a function for filtering head child elements
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which shouldn't be duplicated, like <title/>
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Also adds support for deduplicated `key` properties
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*/
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function unique() {
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const keys = new Set()
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const tags = new Set()
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const metaTypes = new Set()
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const metaCategories: { [metatype: string]: Set<string> } = {}
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return (h: React.ReactElement<any>) => {
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let unique = true
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if (h.key && typeof h.key !== 'number' && h.key.indexOf('$') > 0) {
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const key = h.key.slice(h.key.indexOf('$') + 1)
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if (keys.has(key)) {
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unique = false
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} else {
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keys.add(key)
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}
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}
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// eslint-disable-next-line default-case
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switch (h.type) {
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case 'title':
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case 'base':
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if (tags.has(h.type)) {
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unique = false
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} else {
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tags.add(h.type)
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}
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break
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case 'meta':
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for (let i = 0, len = METATYPES.length; i < len; i++) {
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const metatype = METATYPES[i]
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if (!h.props.hasOwnProperty(metatype)) continue
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if (metatype === 'charSet') {
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if (metaTypes.has(metatype)) {
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unique = false
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} else {
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metaTypes.add(metatype)
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}
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} else {
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const category = h.props[metatype]
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const categories = metaCategories[metatype] || new Set()
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if (categories.has(category)) {
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unique = false
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} else {
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categories.add(category)
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metaCategories[metatype] = categories
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}
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}
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}
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break
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}
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return unique
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}
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}
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/**
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*
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* @param headElements List of multiple <Head> instances
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*/
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function reduceComponents(
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headElements: Array<React.ReactElement<any>>,
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props: WithInAmpMode
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) {
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return headElements
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.reduce(
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(list: React.ReactChild[], headElement: React.ReactElement<any>) => {
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const headElementChildren = React.Children.toArray(
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headElement.props.children
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)
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return list.concat(headElementChildren)
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},
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[]
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)
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.reduce(onlyReactElement, [])
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.reverse()
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.concat(defaultHead(props.inAmpMode))
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.filter(unique())
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.reverse()
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.map((c: React.ReactElement<any>, i: number) => {
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const key = c.key || i
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return React.cloneElement(c, { key })
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})
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}
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const Effect = withSideEffect()
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/**
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* This component injects elements to `<head>` of your page.
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* To avoid duplicated `tags` in `<head>` you can use the `key` property, which will make sure every tag is only rendered once.
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*/
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function Head({ children }: { children: React.ReactNode }) {
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return (
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<AmpStateContext.Consumer>
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{(ampState) => (
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<HeadManagerContext.Consumer>
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{(updateHead) => (
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<Effect
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reduceComponentsToState={reduceComponents}
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handleStateChange={updateHead}
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inAmpMode={isInAmpMode(ampState)}
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>
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{children}
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</Effect>
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)}
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</HeadManagerContext.Consumer>
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)}
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</AmpStateContext.Consumer>
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)
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}
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Head.rewind = Effect.rewind
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export default Head
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