export const REACT_HYDRATION_ERROR_LINK = 'https://react.dev/link/hydration-mismatch' export const NEXTJS_HYDRATION_ERROR_LINK = 'https://nextjs.org/docs/messages/react-hydration-error' /** * Only React 19+ contains component stack diff in the error message */ const errorMessagesWithComponentStackDiff = [ /^In HTML, (.+?) cannot be a child of <(.+?)>\.(.*)\nThis will cause a hydration error\.(.*)/, /^In HTML, (.+?) cannot be a descendant of <(.+?)>\.\nThis will cause a hydration error\.(.*)/, /^In HTML, text nodes cannot be a child of <(.+?)>\.\nThis will cause a hydration error\./, /^In HTML, whitespace text nodes cannot be a child of <(.+?)>\. Make sure you don't have any extra whitespace between tags on each line of your source code\.\nThis will cause a hydration error\./, ] export function isHydrationError(error: Error): boolean { return ( isErrorMessageWithComponentStackDiff(error.message) || /Hydration failed because the server rendered (text|HTML) didn't match the client\./.test( error.message ) || /A tree hydrated but some attributes of the server rendered HTML didn't match the client properties./.test( error.message ) ) } export function isErrorMessageWithComponentStackDiff(msg: string): boolean { return errorMessagesWithComponentStackDiff.some((regex) => regex.test(msg)) } export function getHydrationErrorStackInfo(error: Error): { message: string | null notes: string | null diff: string | null } { const errorMessage = error.message if (isErrorMessageWithComponentStackDiff(errorMessage)) { const [message, diffLog = ''] = errorMessage.split('\n\n') const diff = diffLog.trim() return { message: diff === '' ? errorMessage.trim() : message.trim(), diff, notes: null, } } const [message, maybeComponentStackDiff] = errorMessage.split( `${REACT_HYDRATION_ERROR_LINK}` ) const trimmedMessage = message.trim() // React built-in hydration diff starts with a newline if ( maybeComponentStackDiff !== undefined && maybeComponentStackDiff.length > 1 ) { const diffs: string[] = [] maybeComponentStackDiff.split('\n').forEach((line) => { if (line.trim() === '') return if (!line.trim().startsWith('at ')) { diffs.push(line) } }) const [displayedMessage, ...notes] = trimmedMessage.split('\n\n') return { message: displayedMessage, diff: diffs.join('\n'), notes: notes.join('\n\n') || null, } } else { const [displayedMessage, ...notes] = trimmedMessage.split('\n\n') return { message: displayedMessage, diff: null, notes: notes.join('\n\n'), } } }