--- url: /docs/guide/usage/linter/rules/nextjs/no-duplicate-head.md --- ### What it does Prevent duplicate usage of `` in `pages/_document.js`. ### Why is this bad? This can cause unexpected behavior in your application. ### Examples Examples of **incorrect** code for this rule: ```jsx import Document, { Html, Head, Main, NextScript } from "next/document"; class MyDocument extends Document { static async getInitialProps(ctx) {} render() { return (
); } } export default MyDocument; ``` Examples of **correct** code for this rule: ```jsx import Document, { Html, Head, Main, NextScript } from "next/document"; class MyDocument extends Document { static async getInitialProps(ctx) {} render() { return (
); } } export default MyDocument; ``` ## How to use ## Version This rule was added in v0.3.3. ## References