Nextjs +タイプスクリプト+スタイルのコンポーネント

Rename any of your .js to .tsx . Go ahead and rename your index.js to index.tsx and try to start your server. You will receive an error on CLI that you're trying to use Typescript but you don't have the necessary packages. Run:

npm install --save-dev typescript @types/react @types/node

When you start the server after the ts packages, 2 files are created for you: next-env.d.ts and tsconfig.json .

• next-env.d.ts : Nextjs type declaration file referencing its types inside of your node_modules/next/types/global
• tsconfig.json : contains the compiler options required to compile the project and specifies the root.

Your typescript is ready.

npm install --save styled-components

For testing purposes, make your index.tsx like this:

import styled from "styled-components";

const Title = styled.h1`
  color: red;
`;

const Home = () => {
  return (
    <div>
      <p>hello</p>
      <Title>Title</Title>
    </div>
  );
};

export default Home;

Go to the browser and inspect the Title (h1) element.

Cool! Now you have an incredible JS framework with a powerful style system. But...wait, what if you wanted to reset and/or share styles across all of your pages? Here we go with styled-components' globalStyle .

First, let's start with a Layout component. This is going to wrap every page and has all the shared styles.

Outside the /pages directory, create another folder /layout with Basic.tsx inside:

# /layout
# --/Basic.tsx
# /pages
# --/index.tsx

Inside of Basic.tsx you include and return your shared styles. The trick here is to include the createGlobalStyle and return it on Basic.tsx render.

import { createGlobalStyle } from "styled-components";

export const GlobalStyle = createGlobalStyle`
    // this is the shared style
  html {
    box-sizing: border-box;
  }

  *,
  *::before,
  *::after {
    box-sizing: inherit;
  }

h1 {
    color: yellow !important; // the important is just to show that the style works!
}

  // anything else you would like to include
`;

const BasicLayout = ({ children }: { children: any }) => {
  return (
    <>
      <GlobalStyle />
      {children}
    </>
  );
};

export default BasicLayout;

Returning to pages/index.tsx . Import the newly created BasicLayout component and wrap the Home returned React element with BasicLayout.

import styled from "styled-components";
import BasicLayout from "../layout/Basic";

const Title = styled.h1`
  color: red;
`;

const Home = () => {
  return (
    <BasicLayout>
      <p>hello</p>
      <Title>Title</Title>
    </BasicLayout>
  );
};

export default Home;

From now on, all the pages that include BasicLayout components are going to inherit the styles.

Congratulations!!! Now you have a proper Nextjs + Typescript + styled-component with global styles working!

By default Nextjs allows you to use relative imports. You know, those never-ending imports ../../../../finally.tsx . If you want to use an absolute import, you have to change just one line on tsconfig.json : the baseUrl .

"compilerOptions": {
    // other options
    "baseUrl": "."
  },

Now, all absolute imports start at the same level as the tsconfig.json file. Using the previous pages/index.tsx import as an example, you can change A to B.

// A
import BasicLayout from "../layout/Basic";

// B
import BasicLayout from "layout/Basic";

The fancy term which means: serve the required styles for the first render within the HTML and then load the rest in the client.

You need to create a custom /pages/_document.tsx and copy the following logic into it. That's it.

import Document from 'next/document'
import { ServerStyleSheet } from 'styled-components'

export default class MyDocument extends Document {
  static async getInitialProps(ctx) {
    const sheet = new ServerStyleSheet()
    const originalRenderPage = ctx.renderPage

    try {
      ctx.renderPage = () =>
        originalRenderPage({
          enhanceApp: (App) => (props) =>
            sheet.collectStyles(<App {...props} />),
        })

      const initialProps = await Document.getInitialProps(ctx)
      return {
        ...initialProps,
        styles: (
          <>
            {initialProps.styles}
            {sheet.getStyleElement()}
          </>
        ),
      }
    } finally {
      sheet.seal()
    }
  }
}