import isError from '../../lib/is-error' export function isHydrationError(error: unknown): boolean { return ( isError(error) && (error.message === 'Hydration failed because the initial UI does not match what was rendered on the server.' || error.message === 'Text content does not match server-rendered HTML.') ) } export function isHydrationWarning(message: unknown): message is string { return ( isHtmlTagsWarning(message) || isTextInTagsMismatchWarning(message) || isTextWarning(message) ) } type NullableText = string | null | undefined // https://github.com/facebook/react/blob/main/packages/react-dom/src/__tests__/ReactDOMHydrationDiff-test.js used as a reference const htmlTagsWarnings = new Set([ 'Warning: Expected server HTML to contain a matching <%s> in <%s>.%s', 'Warning: Did not expect server HTML to contain a <%s> in <%s>.%s', ]) const textAndTagsMismatchWarnings = new Set([ 'Warning: Expected server HTML to contain a matching text node for "%s" in <%s>.%s', 'Warning: Did not expect server HTML to contain the text node "%s" in <%s>.%s', ]) const textWarnings = new Set([ 'Warning: Text content did not match. Server: "%s" Client: "%s"%s', ]) export const getHydrationWarningType = ( message: NullableText ): 'tag' | 'text' | 'text-in-tag' => { if (typeof message !== 'string') { // TODO: Doesn't make sense to treat no message as a hydration error message. // We should bail out somewhere earlier. return 'text' } const normalizedMessage = message.startsWith('Warning: ') ? message : `Warning: ${message}` if (isHtmlTagsWarning(normalizedMessage)) return 'tag' if (isTextInTagsMismatchWarning(normalizedMessage)) return 'text-in-tag' return 'text' } const isHtmlTagsWarning = (message: unknown) => typeof message === 'string' && htmlTagsWarnings.has(message) const isTextInTagsMismatchWarning = (msg: unknown) => typeof msg === 'string' && textAndTagsMismatchWarnings.has(msg) const isTextWarning = (msg: unknown) => typeof msg === 'string' && textWarnings.has(msg)