Revert "Revert "Revert "Avoid unnecessary router state changes""" (#3…

…7692)

Revert "Revert "Revert "Avoid unnecessary router state changes"" (#37593)"

This reverts commit 78cbfa0.

packages/next/shared/lib/router/router.ts

@@ -81,37 +81,6 @@ function buildCancellationError() {
  })
 }
 
-function compareRouterStates(a: Router['state'], b: Router['state']) {
- const stateKeys = Object.keys(a)
- if (stateKeys.length !== Object.keys(b).length) return false
-
- for (let i = stateKeys.length; i--; ) {
- const key = stateKeys[i]
- if (key === 'query') {
- const queryKeys = Object.keys(a.query)
- if (queryKeys.length !== Object.keys(b.query).length) {
- return false
- }
- for (let j = queryKeys.length; j--; ) {
- const queryKey = queryKeys[j]
- if (
- !b.query.hasOwnProperty(queryKey) ||
- a.query[queryKey] !== b.query[queryKey]
- ) {
- return false
- }
- }
- } else if (
- !b.hasOwnProperty(key) ||
- a[key as keyof Router['state']] !== b[key as keyof Router['state']]
- ) {
- return false
- }
- }
-
- return true
-}
-
 /**
  * Detects whether a given url is routable by the Next.js router (browser only).
  */
@@ -1372,50 +1341,38 @@ export default class Router implements BaseRouter {
  const shouldScroll = options.scroll ?? !isValidShallowRoute
  const resetScroll = shouldScroll ? { x: 0, y: 0 } : null
 
- const nextScroll = forcedScroll ?? resetScroll
- const mergedNextState = {
- ...nextState,
- route,
- pathname,
- query,
- asPath: cleanedAs,
- isFallback: false,
- }
-
- // for query updates we can skip it if the state is unchanged and we don't
- // need to scroll
- // https://github.com/vercel/next.js/issues/37139
- const canSkipUpdating =
- (options as any)._h &&
- !nextScroll &&
- compareRouterStates(mergedNextState, this.state)
-
- if (!canSkipUpdating) {
- await this.set(mergedNextState, routeInfo, nextScroll).catch((e) => {
- if (e.cancelled) error = error || e
- else throw e
- })
+ await this.set(
+ {
+ ...nextState,
+ route,
+ pathname,
+ query,
+ asPath: cleanedAs,
+ isFallback: false,
+ },
+ routeInfo,
+ forcedScroll ?? resetScroll
+ ).catch((e) => {
+ if (e.cancelled) error = error || e
+ else throw e
+ })
 
-  if (error) {
-  Router.events.emit('routeChangeError', error, cleanedAs, routeProps)
-  throw error
-  }
+ if (error) {
+ Router.events.emit('routeChangeError', error, cleanedAs, routeProps)
+ throw error
+ }
 
- if (process.env.__NEXT_I18N_SUPPORT) {
- if (nextState.locale) {
- document.documentElement.lang = nextState.locale
- }
+ if (process.env.__NEXT_I18N_SUPPORT) {
+ if (nextState.locale) {
+ document.documentElement.lang = nextState.locale
  }
- Router.events.emit('routeChangeComplete', as, routeProps)
+ }
+ Router.events.emit('routeChangeComplete', as, routeProps)
 
- // A hash mark # is the optional last part of a URL
- const hashRegex = /#.+$/
- if (shouldScroll && hashRegex.test(as)) {
- this.scrollToHash(as)
- }
- } else {
- // Still send the event to notify the inital load.
- Router.events.emit('routeChangeComplete', as, routeProps)
+ // A hash mark # is the optional last part of a URL
+ const hashRegex = /#.+$/
+ if (shouldScroll && hashRegex.test(as)) {
+ this.scrollToHash(as)
  }
 
  return true