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Setting <html lang="..."> by default

See original GitHub issue

I’m wondering if there is any way to implicitly set the lang attribute to the html tag. This is a good practice, which improves SEO and a11y.

Currently, my workaround is roughly this:

// ./pages/_document.js
import Document, { Head, Main, NextScript } from 'next/document'

export default class MyDocument extends Document {
  render() {
    return (
      <html lang={this.props.__NEXT_DATA__.props.initialLanguage}>
        <Head />
        <body>
          <Main />
          <NextScript />
        </body>
      </html>
    )
  }
}

If there is no way to inject lang automatically, shall it be mentioned in the example or plugin docs?

Issue Analytics

State:
Created 5 years ago
Reactions:9
Comments:44 (30 by maintainers)

Top GitHub Comments

6reactions

eric-burelcommented, Jul 15, 2020

Ok so a more robust code is as follow:

// i18next-http-middleware is in charge of enhancing the req object
interface IncomingMessageWithI18n extends IncomingMessage {
  language?: string;
  i18n: any;
}
export const i18nPropsFromCtx = (
  ctx: NextPageContext
): Partial<HtmlLanguageProps> => {
  if (!(ctx && ctx.req && (ctx.req as IncomingMessageWithI18n).language))
    return {};
  const req = ctx.req as IncomingMessageWithI18n;
  return {
    lang: req.language,
    dir: req.i18n && req.i18n.dir(req.language),
  };
};

and in plain JS:

export const i18nPropsFromCtx = (ctx) => {
  if (!(ctx && ctx.req && ctx.req.language))
    return {};
  const req = ctx.req;
  return {
    lang: req.language,
    dir: req.i18n && req.i18n.dir(req.language),
  };
};

Use that in your custom _document getInitialProps call:

MyDocument.getInitialProps = async (ctx) => {
  const i18nDocumentProps = i18nPropsFromCtx(ctx);
  return {
    i18nDocumentProps,
  };
};

and then finally:

export default class MyDocument extends Document {
  render() {
    const { i18nDocumentProps } = this.props;
    return (
      <Html
        {...i18nDocumentProps}
      >
....

Thanks all for your fast answers!

5reactions

felixmoshcommented, Nov 26, 2019

I’ve found out that i18next-express-middleware that is applied by next-i18next-middleware is attaching language & languageDirection on res.locals.

So the code may look like:

export default class MyDocument extends Document {
  static async getInitialProps(ctx) {
    const initialProps = await Document.getInitialProps(ctx);
    const {
      res: { locals },
    } = ctx;
    const additionalProps = {
      languageDirection: locals.languageDirection,
      language: locals.language,
    };

    return { ...initialProps, ...additionalProps };
  }

  render() {
    const { languageDirection, language } = this.props;
    return (
      <html lang={language} dir={languageDirection}>
        <Head />
        <body>
          <Main />
          <NextScript />
        </body>
      </html>
    );
  }
}