hedgedoc/frontend/src/extensions/extra-integrations/highlighted-code-fence/hooks/use-code-dom.tsx
Tilman Vatteroth e390c0dd15 fix(frontend): reformat source files
Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>
2022-12-04 20:59:46 +01:00

66 lines
2.3 KiB
TypeScript

/*
* SPDX-FileCopyrightText: 2022 The HedgeDoc developers (see AUTHORS file)
*
* SPDX-License-Identifier: AGPL-3.0-only
*/
import convertHtmlToReact from '@hedgedoc/html-to-react'
import { sanitize } from 'dompurify'
import type { HLJSApi } from 'highlight.js'
import type { ReactElement } from 'react'
import React, { Fragment, useMemo } from 'react'
/**
* Highlights the given code using highlight.js. If the language wasn't recognized then it won't be highlighted.
*
* @param code The code to highlight
* @param hljs The highlight.js API. Needs to be imported or lazy loaded.
* @param language The language of the code to use for highlighting
* @return The react elements that represent the highlighted code
*/
export const useCodeDom = (code: string, hljs: HLJSApi | undefined, language?: string): ReactElement[] | undefined => {
return useMemo(() => {
if (!hljs) {
return
}
if (!!language && hljs.listLanguages().includes(language)) {
const highlightedHtml = hljs.highlight(code, { language }).value
return createHtmlLinesToReactDOM(omitNewLineAtEnd(highlightedHtml).split('\n'))
} else {
return createPlaintextToReactDOM(code)
}
}, [code, hljs, language])
}
/**
* Converts the given html code to react elements without any custom transformation but with sanitizing.
*
* @param code The code to convert
* @return the code represented as react elements
*/
const createHtmlLinesToReactDOM = (code: string[]): ReactElement[] => {
return code.map((line, lineIndex) => <Fragment key={lineIndex}>{convertHtmlToReact(sanitize(line))}</Fragment>)
}
/**
* Converts the given line based text to plain text react elements but without interpreting them as html first.
*
* @param text The text to convert
* @return the text represented as react elements.
*/
const createPlaintextToReactDOM = (text: string): ReactElement[] => {
return text.split('\n').map((line, lineIndex) => React.createElement('span', { key: lineIndex }, line))
}
/**
* Returns the given code but without the last new line if the string ends with a new line.
*
* @param code The code to inspect
* @return the modified code
*/
const omitNewLineAtEnd = (code: string): string => {
if (code.endsWith('\n')) {
return code.slice(0, -1)
} else {
return code
}
}