🚀 Next.js Revalidating (Easy Notes)

📌 1. Revalidation kya hota hai?

👉 Simple:

👉 Why needed?

👉 Example:

👉 Automatic update after time

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import { cacheLife } from "next/cache"

export async function getData() {
  "use cache"
  cacheLife("hours")
}

👉 1 hour baad auto refresh

📌 Defined using cacheLife

👉 Manual update (best 🔥)

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import { cacheTag } from "next/cache"

export async function getProducts() {
  "use cache"
  cacheTag("products")
}

👉 Data ko tag diya

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import { revalidateTag } from "next/cache"

export async function updateData() {
  // DB update
  revalidateTag("products")
}

👉 Old data show hoga

👉 New data background me load hoga

📌 stale-while-revalidate concept

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import { updateTag } from "next/cache"

export async function createPost() {
  // DB save
  updateTag("posts")
}

👉 Immediate update

👉 User ko instantly new data dikhega

FeatureupdateTagrevalidateTagUpdateInstantBackgroundUXLatest dataSlight delayUse caseCreate/update formBlog/products

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import { revalidatePath } from "next/cache"

export async function updateUser() {
  revalidatePath("/profile")
}

👉 Entire page refresh

📌 Use when tag pata nahi ho

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cacheLife({
  stale: 3600,
  revalidate: 7200,
  expire: 86400
})

👉 Full control

👉 Simple rule:

👉 Cache fast hai

👉 Revalidation fresh data deta hai

👉 updateTag = instant

👉 revalidateTag = background

👉 "Next.js me caching fast hai aur revalidation usko fresh banata hai"