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Reorganize redux and hooks (1/4) (#985)

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Signed-off-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>
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Tilman Vatteroth 2021-02-01 22:55:49 +01:00 • committed by GitHub
parent bdf8110676
commit 1b7abf9f27
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61 changed files with 898 additions and 986 deletions
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23
src/components/markdown-renderer/hooks/use-extract-first-headline.ts
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@ -4,10 +4,14 @@
* SPDX-License-Identifier: AGPL-3.0-only
*/
import React, { useCallback, useEffect } from 'react'
import React, { useCallback, useEffect, useRef } from 'react'
export const useExtractFirstHeadline = (documentElement: React.RefObject<HTMLDivElement>, content: string, onFirstHeadingChange?: (firstHeading: string | undefined) => void): void => {
const extractInnerText = useCallback((node: ChildNode): string => {
const extractInnerText = useCallback((node: ChildNode | null): string => {
if (!node) {
return ''
}
let innerText = ''
if ((node as HTMLElement).classList?.contains("katex-mathml")) {
@ -15,7 +19,9 @@ export const useExtractFirstHeadline = (documentElement: React.RefObject<HTMLDiv
}
if (node.childNodes && node.childNodes.length > 0) {
node.childNodes.forEach((child) => { innerText += extractInnerText(child) })
node.childNodes.forEach((child) => {
innerText += extractInnerText(child)
})
} else if (node.nodeName === 'IMG') {
innerText += (node as HTMLImageElement).getAttribute('alt')
} else {
@ -24,14 +30,17 @@ export const useExtractFirstHeadline = (documentElement: React.RefObject<HTMLDiv
return innerText
}, [])
const lastFirstHeading = useRef<string | undefined>()
useEffect(() => {
if (onFirstHeadingChange && documentElement.current) {
const firstHeading = documentElement.current.getElementsByTagName('h1').item(0)
if (firstHeading) {
onFirstHeadingChange(extractInnerText(firstHeading))
} else {
onFirstHeadingChange(undefined)
const headingText = extractInnerText(firstHeading)
if (headingText === lastFirstHeading.current) {
return
}
lastFirstHeading.current = headingText
onFirstHeadingChange(headingText)
}
}, [documentElement, extractInnerText, onFirstHeadingChange, content])
}