The relationship between pages/_app.js and pages/index.js in a Next.js

By -

The relationship between pages/_app.js and pages/index.js in a Next.js application is foundational to how Next.js handles page rendering and application structure. Here's an overview of their roles and interplay:

  1. pages/_app.js - The Custom App Component:

    • This is a special file in Next.js that allows you to override the default App component used by Next.js.
    • It's the top-level component that gets executed for every page visit. It's useful for implementing application-wide page layouts or injecting additional data into pages.
    • Whatever you include in _app.js (like global CSS, layout components, context providers) is accessible in every page of your application.
    • It receives a Component prop, which is the active page being rendered (e.g., the content of pages/index.js or any other page), and pageProps, which are props specific to each page.

  2. pages/index.js - A Page Component:

    • This file represents the homepage of your Next.js application. It's what gets rendered when users visit the root URL (/).
    • It's just one of potentially many page components in your pages directory. Each file in the pages directory corresponds to a route in your application, with index.js being the default route.
    • The content of pages/index.js (or any other page) gets rendered as the Component prop inside _app.js.

  3. How They Work Together:

    • When a user visits a page in a Next.js app, Next.js first executes _app.js. The Component prop in _app.js is set to the current page component (like pages/index.js for the homepage).
    • Any props that are fetched during server-side rendering, static generation, or client-side rendering are passed to the page component as pageProps.
    • _app.js wraps around the current page, meaning any layouts, context providers, or global styles you define in _app.js will apply to all your pages, including pages/index.js.

In summary, pages/_app.js acts as a wrapper around all page components (including pages/index.js). It's where you implement logic, styles, or components that should be available across all pages of your application. pages/index.js, on the other hand, is specifically for the content and logic of the homepage.

Comments

Post a Comment

Popular posts from this blog

WSL2配置proxychains, 使得终端走宿主机代理

By -
安装：           sudo apt-get update           sudo apt-get upgrade           sudo apt-get install proxychains4 获得宿主机 IP： cat /etc/resolv.conf | grep nameserver | awk '{ print $2 }' 查询代理软件端口：10810 编辑配置文件：sudo nano /etc/proxychains4.conf           change：socks4 127.0.0.1 9095         to：socks5 xxx.xxx.xxx.xxx 10810         中间的x是上面查出来的ip地址，10810是v2rayN局域网（不是本地）监听的端口。          并在 [ProxyList]之前添加：           # Exclude localhost           localnet 127.0.0.0/255.0.0.0 测试：           proxychains4 curl -L myip.ipip.net           proxychains4 curl -L cip.cc vscode走代理：proxychains4 code . 更新proxychains:           sudo apt-get update # This will update the list of available ...
Read more

Javascript Currying

By -
Transform a function with multiple parameters into calling a nesting function multiple times with one parameter; the functionality of the two situations is not changed. For example, the following functions have the same functionality but different formats: // original format function add(a, b) { return a + b; } // currying format function curryingAddFirst(a) { return function (b) { return a + b; }; } // currying format with arrow function const curryingAddSecond = (a) => (b) => a + b;
Read more

In the process of data transfer, what are differences between server side sessions and authentication tokens?

By -
Server-side sessions and authentication tokens are both methods used to authenticate users and maintain their state over the internet. However, they differ in how they store and manage this information. Server-Side Sessions In server-side sessions, the user state is stored on the server's memory. When a user logs in, the server creates and stores the session data (such as user account data and role) in its memory. The server then sends a session ID to the user's browser, which is typically stored in a cookie. This session ID is sent back to the server with each subsequent request, allowing the server to recognize and authenticate the user. This method requires the server to keep track of active sessions, which can consume significant memory resources if there are many concurrent users . Authentication Tokens Authentication tokens, on the other hand, encapsulate the user state within the token itself. When a user logs in, the server generates a token that contains user informati...
Read more