cacheTag

The cacheTag function allows you to tag cached data for on-demand invalidation. By associating tags with cache entries, you can selectively purge or revalidate specific cache entries without affecting other cached data.

Usage

To use cacheTag, enable the dynamicIO flag in your next.config.js file:

import type { NextConfig } from 'next'

const nextConfig: NextConfig = {
  experimental: {
    dynamicIO: true,
  },
}

export default nextConfig

The cacheTag function takes a single string value, or a string array.

import { unstable_cacheTag as cacheTag } from 'next/cache'

export async function getData() {
  'use cache'
  cacheTag('my-data')
  const data = await fetch('/api/data')
  return data
}

You can then purge the cache on-demand using revalidateTag API in another function, for example, a route handler or Server Action:

'use server'

import { revalidateTag } from 'next/cache'

export default async function submit() {
  await addPost()
  revalidateTag('my-data')
}

Good to know

Idempotent Tags: Applying the same tag multiple times has no additional effect.
Multiple Tags: You can assign multiple tags to a single cache entry by passing an array to cacheTag.

cacheTag('tag-one', 'tag-two')

Examples

Tagging components or functions

Tag your cached data by calling cacheTag within a cached function or component:

import { unstable_cacheTag as cacheTag } from 'next/cache'

interface BookingsProps {
  type: string
}

export async function Bookings({ type = 'haircut' }: BookingsProps) {
  'use cache'
  cacheTag('bookings-data')

  async function getBookingsData() {
    const data = await fetch(`/api/bookings?type=${encodeURIComponent(type)}`)
    return data
  }

  return //...
}

Creating tags from external data

You can use the data returned from an async function to tag the cache entry.

import { unstable_cacheTag as cacheTag } from 'next/cache'

interface BookingsProps {
  type: string
}

export async function Bookings({ type = 'haircut' }: BookingsProps) {
  async function getBookingsData() {
    'use cache'
    const data = await fetch(`/api/bookings?type=${encodeURIComponent(type)}`)
    cacheTag('bookings-data', data.id)
    return data
  }
  return //...
}

Invalidating tagged cache

Using revalidateTag, you can invalidate the cache for a specific tag when needed:

'use server'

import { revalidateTag } from 'next/cache'

export async function updateBookings() {
  await updateBookingData()
  revalidateTag('bookings-data')
}

Usage

Good to know

Examples

Tagging components or functions

Creating tags from external data

Invalidating tagged cache

dynamicIO

use cache

revalidateTag

cacheLife

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