import type { WorkStore } from '../app-render/work-async-storage.external' import type { FallbackRouteParams } from './fallback-params' import { ReflectAdapter } from '../web/spec-extension/adapters/reflect' import { throwToInterruptStaticGeneration, postponeWithTracking, trackSynchronousRequestDataAccessInDev, } from '../app-render/dynamic-rendering' import { workUnitAsyncStorage, type PrerenderStore, type PrerenderStorePPR, type PrerenderStoreLegacy, type PrerenderStoreModern, } from '../app-render/work-unit-async-storage.external' import { InvariantError } from '../../shared/lib/invariant-error' import { describeStringPropertyAccess, wellKnownProperties, } from '../../shared/lib/utils/reflect-utils' import { makeHangingPromise } from '../dynamic-rendering-utils' import { createDedupedByCallsiteServerErrorLoggerDev } from '../create-deduped-by-callsite-server-error-logger' import { scheduleImmediate } from '../../lib/scheduler' import { dynamicAccessAsyncStorage } from '../app-render/dynamic-access-async-storage.external' export type ParamValue = string | Array | undefined export type Params = Record /** * In this version of Next.js the `params` prop passed to Layouts, Pages, and other Segments is a Promise. * However to facilitate migration to this new Promise type you can currently still access params directly on the Promise instance passed to these Segments. * The `UnsafeUnwrappedParams` type is available if you need to temporarily access the underlying params without first awaiting or `use`ing the Promise. * * In a future version of Next.js the `params` prop will be a plain Promise and this type will be removed. * * Typically instances of `params` can be updated automatically to be treated as a Promise by a codemod published alongside this Next.js version however if you * have not yet run the codemod of the codemod cannot detect certain instances of `params` usage you should first try to refactor your code to await `params`. * * If refactoring is not possible but you still want to be able to access params directly without typescript errors you can cast the params Promise to this type * * ```tsx * type Props = { params: Promise<{ id: string }>} * * export default async function Layout(props: Props) { * const directParams = (props.params as unknown as UnsafeUnwrappedParams) * return ... * } * ``` * * This type is marked deprecated to help identify it as target for refactoring away. * * @deprecated */ export type UnsafeUnwrappedParams

= P extends Promise ? Omit : never export function createParamsFromClient( underlyingParams: Params, workStore: WorkStore ) { const workUnitStore = workUnitAsyncStorage.getStore() if (workUnitStore) { switch (workUnitStore.type) { case 'prerender': case 'prerender-client': case 'prerender-ppr': case 'prerender-legacy': return createPrerenderParams(underlyingParams, workStore, workUnitStore) case 'cache': case 'private-cache': case 'unstable-cache': throw new InvariantError( 'createParamsFromClient should not be called in cache contexts.' ) case 'request': break default: workUnitStore satisfies never } } return createRenderParams(underlyingParams, workStore) } // generateMetadata always runs in RSC context so it is equivalent to a Server Page Component export type CreateServerParamsForMetadata = typeof createServerParamsForMetadata export const createServerParamsForMetadata = createServerParamsForServerSegment // routes always runs in RSC context so it is equivalent to a Server Page Component export function createServerParamsForRoute( underlyingParams: Params, workStore: WorkStore ) { const workUnitStore = workUnitAsyncStorage.getStore() if (workUnitStore) { switch (workUnitStore.type) { case 'prerender': case 'prerender-client': case 'prerender-ppr': case 'prerender-legacy': return createPrerenderParams(underlyingParams, workStore, workUnitStore) case 'cache': case 'private-cache': case 'unstable-cache': throw new InvariantError( 'createServerParamsForRoute should not be called in cache contexts.' ) case 'request': break default: workUnitStore satisfies never } } return createRenderParams(underlyingParams, workStore) } export function createServerParamsForServerSegment( underlyingParams: Params, workStore: WorkStore ): Promise { const workUnitStore = workUnitAsyncStorage.getStore() if (workUnitStore) { switch (workUnitStore.type) { case 'prerender': case 'prerender-client': case 'prerender-ppr': case 'prerender-legacy': return createPrerenderParams(underlyingParams, workStore, workUnitStore) case 'cache': case 'private-cache': case 'unstable-cache': throw new InvariantError( 'createServerParamsForServerSegment should not be called in cache contexts.' ) case 'request': break default: workUnitStore satisfies never } } return createRenderParams(underlyingParams, workStore) } export function createPrerenderParamsForClientSegment( underlyingParams: Params ): Promise { const workUnitStore = workUnitAsyncStorage.getStore() if (workUnitStore) { switch (workUnitStore.type) { case 'prerender': case 'prerender-client': const fallbackParams = workUnitStore.fallbackRouteParams if (fallbackParams) { for (let key in underlyingParams) { if (fallbackParams.has(key)) { // This params object has one or more fallback params, so we need // to consider the awaiting of this params object "dynamic". Since // we are in cacheComponents mode we encode this as a promise that never // resolves. return makeHangingPromise(workUnitStore.renderSignal, '`params`') } } } break case 'cache': case 'private-cache': case 'unstable-cache': throw new InvariantError( 'createPrerenderParamsForClientSegment should not be called in cache contexts.' ) case 'prerender-ppr': case 'prerender-legacy': case 'request': break default: workUnitStore satisfies never } } // We're prerendering in a mode that does not abort. We resolve the promise without // any tracking because we're just transporting a value from server to client where the tracking // will be applied. return Promise.resolve(underlyingParams) } function createPrerenderParams( underlyingParams: Params, workStore: WorkStore, prerenderStore: PrerenderStore ): Promise { switch (prerenderStore.type) { case 'prerender': case 'prerender-client': { const fallbackParams = prerenderStore.fallbackRouteParams if (fallbackParams) { for (const key in underlyingParams) { if (fallbackParams.has(key)) { // This params object has one or more fallback params, so we need // to consider the awaiting of this params object "dynamic". Since // we are in cacheComponents mode we encode this as a promise that never // resolves. return makeHangingParams(underlyingParams, prerenderStore) } } } break } case 'prerender-ppr': { const fallbackParams = prerenderStore.fallbackRouteParams if (fallbackParams) { for (const key in underlyingParams) { if (fallbackParams.has(key)) { return makeErroringExoticParams( underlyingParams, fallbackParams, workStore, prerenderStore ) } } } break } case 'prerender-legacy': break default: prerenderStore satisfies never } if (process.env.__NEXT_CACHE_COMPONENTS) { return makeUntrackedParams(underlyingParams) } else { return makeUntrackedExoticParams(underlyingParams) } } function createRenderParams( underlyingParams: Params, workStore: WorkStore ): Promise { if (process.env.NODE_ENV === 'development' && !workStore.isPrefetchRequest) { if (process.env.__NEXT_CACHE_COMPONENTS) { return makeDynamicallyTrackedParamsWithDevWarnings( underlyingParams, workStore ) } return makeDynamicallyTrackedExoticParamsWithDevWarnings( underlyingParams, workStore ) } else { if (process.env.__NEXT_CACHE_COMPONENTS) { return makeUntrackedParams(underlyingParams) } return makeUntrackedExoticParams(underlyingParams) } } interface CacheLifetime {} const CachedParams = new WeakMap>() const fallbackParamsProxyHandler: ProxyHandler> = { get: function get(target, prop, receiver) { if (prop === 'then' || prop === 'catch' || prop === 'finally') { const originalMethod = ReflectAdapter.get(target, prop, receiver) return { [prop]: (...args: unknown[]) => { const store = dynamicAccessAsyncStorage.getStore() if (store) { store.abortController.abort( new Error(`Accessed fallback \`params\` during prerendering.`) ) } return new Proxy( originalMethod.apply(target, args), fallbackParamsProxyHandler ) }, }[prop] } return ReflectAdapter.get(target, prop, receiver) }, } function makeHangingParams( underlyingParams: Params, prerenderStore: PrerenderStoreModern ): Promise { const cachedParams = CachedParams.get(underlyingParams) if (cachedParams) { return cachedParams } const promise = new Proxy( makeHangingPromise(prerenderStore.renderSignal, '`params`'), fallbackParamsProxyHandler ) CachedParams.set(underlyingParams, promise) return promise } function makeErroringExoticParams( underlyingParams: Params, fallbackParams: FallbackRouteParams, workStore: WorkStore, prerenderStore: PrerenderStorePPR | PrerenderStoreLegacy ): Promise { const cachedParams = CachedParams.get(underlyingParams) if (cachedParams) { return cachedParams } const augmentedUnderlying = { ...underlyingParams } // We don't use makeResolvedReactPromise here because params // supports copying with spread and we don't want to unnecessarily // instrument the promise with spreadable properties of ReactPromise. const promise = Promise.resolve(augmentedUnderlying) CachedParams.set(underlyingParams, promise) Object.keys(underlyingParams).forEach((prop) => { if (wellKnownProperties.has(prop)) { // These properties cannot be shadowed because they need to be the // true underlying value for Promises to work correctly at runtime } else { if (fallbackParams.has(prop)) { Object.defineProperty(augmentedUnderlying, prop, { get() { const expression = describeStringPropertyAccess('params', prop) // In most dynamic APIs we also throw if `dynamic = "error"` however // for params is only dynamic when we're generating a fallback shell // and even when `dynamic = "error"` we still support generating dynamic // fallback shells // TODO remove this comment when cacheComponents is the default since there // will be no `dynamic = "error"` if (prerenderStore.type === 'prerender-ppr') { // PPR Prerender (no cacheComponents) postponeWithTracking( workStore.route, expression, prerenderStore.dynamicTracking ) } else { // Legacy Prerender throwToInterruptStaticGeneration( expression, workStore, prerenderStore ) } }, enumerable: true, }) Object.defineProperty(promise, prop, { get() { const expression = describeStringPropertyAccess('params', prop) // In most dynamic APIs we also throw if `dynamic = "error"` however // for params is only dynamic when we're generating a fallback shell // and even when `dynamic = "error"` we still support generating dynamic // fallback shells // TODO remove this comment when cacheComponents is the default since there // will be no `dynamic = "error"` if (prerenderStore.type === 'prerender-ppr') { // PPR Prerender (no cacheComponents) postponeWithTracking( workStore.route, expression, prerenderStore.dynamicTracking ) } else { // Legacy Prerender throwToInterruptStaticGeneration( expression, workStore, prerenderStore ) } }, set(newValue) { Object.defineProperty(promise, prop, { value: newValue, writable: true, enumerable: true, }) }, enumerable: true, configurable: true, }) } else { ;(promise as any)[prop] = underlyingParams[prop] } } }) return promise } function makeUntrackedExoticParams(underlyingParams: Params): Promise { const cachedParams = CachedParams.get(underlyingParams) if (cachedParams) { return cachedParams } // We don't use makeResolvedReactPromise here because params // supports copying with spread and we don't want to unnecessarily // instrument the promise with spreadable properties of ReactPromise. const promise = Promise.resolve(underlyingParams) CachedParams.set(underlyingParams, promise) Object.keys(underlyingParams).forEach((prop) => { if (wellKnownProperties.has(prop)) { // These properties cannot be shadowed because they need to be the // true underlying value for Promises to work correctly at runtime } else { ;(promise as any)[prop] = underlyingParams[prop] } }) return promise } function makeUntrackedParams(underlyingParams: Params): Promise { const cachedParams = CachedParams.get(underlyingParams) if (cachedParams) { return cachedParams } const promise = Promise.resolve(underlyingParams) CachedParams.set(underlyingParams, promise) return promise } function makeDynamicallyTrackedExoticParamsWithDevWarnings( underlyingParams: Params, store: WorkStore ): Promise { const cachedParams = CachedParams.get(underlyingParams) if (cachedParams) { return cachedParams } // We don't use makeResolvedReactPromise here because params // supports copying with spread and we don't want to unnecessarily // instrument the promise with spreadable properties of ReactPromise. const promise = new Promise((resolve) => scheduleImmediate(() => resolve(underlyingParams)) ) const proxiedProperties = new Set() const unproxiedProperties: Array = [] Object.keys(underlyingParams).forEach((prop) => { if (wellKnownProperties.has(prop)) { // These properties cannot be shadowed because they need to be the // true underlying value for Promises to work correctly at runtime unproxiedProperties.push(prop) } else { proxiedProperties.add(prop) ;(promise as any)[prop] = underlyingParams[prop] } }) const proxiedPromise = new Proxy(promise, { get(target, prop, receiver) { if (typeof prop === 'string') { if ( // We are accessing a property that was proxied to the promise instance proxiedProperties.has(prop) ) { const expression = describeStringPropertyAccess('params', prop) syncIODev(store.route, expression) } } return ReflectAdapter.get(target, prop, receiver) }, set(target, prop, value, receiver) { if (typeof prop === 'string') { proxiedProperties.delete(prop) } return ReflectAdapter.set(target, prop, value, receiver) }, ownKeys(target) { const expression = '`...params` or similar expression' syncIODev(store.route, expression, unproxiedProperties) return Reflect.ownKeys(target) }, }) CachedParams.set(underlyingParams, proxiedPromise) return proxiedPromise } // Similar to `makeDynamicallyTrackedExoticParamsWithDevWarnings`, but just // logging the sync access without actually defining the params on the promise. function makeDynamicallyTrackedParamsWithDevWarnings( underlyingParams: Params, store: WorkStore ): Promise { const cachedParams = CachedParams.get(underlyingParams) if (cachedParams) { return cachedParams } // We don't use makeResolvedReactPromise here because params // supports copying with spread and we don't want to unnecessarily // instrument the promise with spreadable properties of ReactPromise. const promise = new Promise((resolve) => scheduleImmediate(() => resolve(underlyingParams)) ) const proxiedProperties = new Set() const unproxiedProperties: Array = [] Object.keys(underlyingParams).forEach((prop) => { if (wellKnownProperties.has(prop)) { // These properties cannot be shadowed because they need to be the // true underlying value for Promises to work correctly at runtime unproxiedProperties.push(prop) } else { proxiedProperties.add(prop) } }) const proxiedPromise = new Proxy(promise, { get(target, prop, receiver) { if (typeof prop === 'string') { if ( // We are accessing a property that was proxied to the promise instance proxiedProperties.has(prop) ) { const expression = describeStringPropertyAccess('params', prop) warnForSyncAccess(store.route, expression) } } return ReflectAdapter.get(target, prop, receiver) }, set(target, prop, value, receiver) { if (typeof prop === 'string') { proxiedProperties.delete(prop) } return ReflectAdapter.set(target, prop, value, receiver) }, ownKeys(target) { const expression = '`...params` or similar expression' warnForIncompleteEnumeration(store.route, expression, unproxiedProperties) return Reflect.ownKeys(target) }, }) CachedParams.set(underlyingParams, proxiedPromise) return proxiedPromise } function syncIODev( route: string | undefined, expression: string, missingProperties?: Array ) { const workUnitStore = workUnitAsyncStorage.getStore() if (workUnitStore) { switch (workUnitStore.type) { case 'request': if (workUnitStore.prerenderPhase === true) { // When we're rendering dynamically in dev, we need to advance out of // the Prerender environment when we read Request data synchronously. trackSynchronousRequestDataAccessInDev(workUnitStore) } break case 'prerender': case 'prerender-client': case 'prerender-ppr': case 'prerender-legacy': case 'cache': case 'private-cache': case 'unstable-cache': break default: workUnitStore satisfies never } } // In all cases we warn normally if (missingProperties && missingProperties.length > 0) { warnForIncompleteEnumeration(route, expression, missingProperties) } else { warnForSyncAccess(route, expression) } } const warnForSyncAccess = createDedupedByCallsiteServerErrorLoggerDev( createParamsAccessError ) const warnForIncompleteEnumeration = createDedupedByCallsiteServerErrorLoggerDev(createIncompleteEnumerationError) function createParamsAccessError( route: string | undefined, expression: string ) { const prefix = route ? `Route "${route}" ` : 'This route ' return new Error( `${prefix}used ${expression}. ` + `\`params\` should be awaited before using its properties. ` + `Learn more: https://nextjs.org/docs/messages/sync-dynamic-apis` ) } function createIncompleteEnumerationError( route: string | undefined, expression: string, missingProperties: Array ) { const prefix = route ? `Route "${route}" ` : 'This route ' return new Error( `${prefix}used ${expression}. ` + `\`params\` should be awaited before using its properties. ` + `The following properties were not available through enumeration ` + `because they conflict with builtin property names: ` + `${describeListOfPropertyNames(missingProperties)}. ` + `Learn more: https://nextjs.org/docs/messages/sync-dynamic-apis` ) } function describeListOfPropertyNames(properties: Array) { switch (properties.length) { case 0: throw new InvariantError( 'Expected describeListOfPropertyNames to be called with a non-empty list of strings.' ) case 1: return `\`${properties[0]}\`` case 2: return `\`${properties[0]}\` and \`${properties[1]}\`` default: { let description = '' for (let i = 0; i < properties.length - 1; i++) { description += `\`${properties[i]}\`, ` } description += `, and \`${properties[properties.length - 1]}\`` return description } } }