markdownit how to use highlight

[bookyo]

i write markdown content.
after $md.render() ：

<pre><code class="language-javascript">var a=123
console.log(2323)
println(2323)
</code></pre>

highlight is not work,.
my nuxt.config.js:

markdownit: {
    breaks: true,
    linkify: true,
    injected: true,
    langPrefix: "language-"
  },

_{This question is available on Nuxt community (#c142)}

[ghost]

This issue as been imported as question since it does not respect modules issue template. Only bug reports and feature requests stays open to reduce maintainers workload.
If your issue is not a question, please mention the repo admin or moderator to change its type and it will be re-opened automatically.
Your question is available at https://cmty.app/nuxt/modules/issues/c142.

[mmintel]

@bookyo did you find a solution?

[fulopkovacs]

@bookyo @mmintel I got it working in 3 steps:

After installing markdownit (npm install @nuxtjs/markdownit):

// nuxt.config.js

export default {
    ....
    // 1.) add markdown-it to modules:
    modules: [
        '@nuxtjs/markdownit',
    ],
    css: [
        // 2.) use a style for syntax highlighting
        'highlight.js/styles/github.css'
    ]
    ....
    markdownit: {
      // 3.) use syntax highlighting:
      highlight: function(str, lang) {
        if (lang && hljs.getLanguage(lang)) {
          try {
            return hljs.highlight(lang, str).value
          } catch (__) {}                                                                                        
          return '' // use external default escaping
        }
      }
    },
    ...
}

You can use different styles, check out this list.

It's been working for me so far, so I hope it'll help you too! ☺️

That weird highlight method is from the official and original markdown-it docs by the way (https://github.com/markdown-it/markdown-it#syntax-highlighting).

[MoonCheung]

@fulopkovacs I follow the code method you provided and it still doesn't work. How can I solve the problem so that markdown-it can highlight the syntax

[frikishaan]

@fulopkovacs I follow the code method you provided and it still doesn't work. How can I solve the problem so that markdown-it can highlight the syntax

You can try this, it works for me in nuxt.js

highlight: function (str, lang) {
    if (lang && hljs.getLanguage(lang)) {
      try {
        return '<pre class="hljs"><code>' +
               hljs.highlight(lang, str, true).value +
               '</code></pre>';
      } catch (__) {}
    }

    return '<pre class="hljs"><code>' + md.utils.escapeHtml(str) + '</code></pre>';
  }

Reference - https://markdown-it.github.io/markdown-it/

[ChucKN0risK]

I also have issues making highlight.js work with @nuxt/markdown-it.

I want to display formatted code in my article pages whose content comes from an API.

I get the following error when my article page loads: hljs is not defined in _slug.vue.

nuxt.config.js:

const hljs = require('highlight.js');

module.exports = async () => {
  return {
    modules: [
      '@nuxtjs/markdownit',
    ],

    markdownit: {
      html: true,
      preset: 'default',
      linkify: true,
      breaks: true,
      injected: true,
      highlight: function (str, lang) {
        // ➡️ hljs is undefined here ⬅️ 😢
        if (lang && hljs.getLanguage(lang)) {
          try {
            return '<pre class="hljs"><code>' +
                   hljs.highlight(lang, str, true).value +
                   '</code></pre>';
          } catch (__) {}
        }
        return '<pre class="hljs"><code>' + md.utils.escapeHtml(str) + '</code></pre>';
      }
    },
  }
}

_slug.vue:

<template>
  <div>
    <main-header />
    <main>
      <sp-section>
        <div
          v-html="articleContent"
        />
      </sp-section>
    </main>
  </div>
</template>

<script>
  import hljs from 'highlight.js';

  export default {
    async asyncData({ app, params }) {
      try {
        const [ article ] = await app.$axios.$get(`http://localhost:1337/articles/?slug=${params.slug}`);
        return {
          article,
        };
      } catch (err) {
        return false;
      }
    },
    computed: {
      articleContent() {
        return this.$md.render(this.article.content);
      },
    },
  };
</script>

[fulopkovacs]

@ChucKN0risK
Hmmm, are you sure that you need to import hls from highlight.js in _slug.vue? I took a quick glance at my repo, and I imported it only in nuxt.config.js. I'm still at work, but I'll look into the problem after I finished.

[ChucKN0risK]

@fulopkovacs No I'm not sure I should import it inside _slug.vue. I only tried because of the error I had telling me that hljs is undefined in _slug.vue 😉

[ChucKN0risK]

@fulopkovacs Did you have any chance of checking my issue? Thanks in advance ;)

[fulopkovacs]

@ChucKN0risK I did look into it, but couldn't find anything in my local setup. I am definitely not an expert (not event a front-end dev by now), but the only thing I can think of is that maybe the markdownit nuxt plugin is not able to display asynchronously fetched content, since it uses markdownit-loader for preprocessing markdown-files (= convert them to html) on the server side. If I were you I'd check out the markdown-it markdown parser (this is actually the library that the markdownit nuxt plugin uses for parsing md). It can be used with highlightjs, and loaded from a cdn if you want to use it in the browser.

Again, I'm not an expert, and I might be wrong about the markdownit nuxt plugin, but I'm pretty sure that the markdown-it library could help you. To be honest, I'm probably not be the best person to help, since I've never used nuxt in production. I found that Hugo fits my needs a lot better (I use it for my personal blog). Oh, and sorry for the late response, I looked at the problem on the day I first replied, but didn't want to get back to you empty-handed. Time itself could not solve this problem though... 😅

[ChucKN0risK]

@fulopkovacs Thanks for taking the time to answer me ;) I managed to directly use mardown-it inside my _slug.vue component like so:

export default {
  async asyncData({ app, params }) {
    try {
      const [ article ] = await app.$axios.$get(`http://localhost:1337/articles/?slug=${params.slug}`);
      const content = markdownit({
        html: true,
        preset: 'default',
        linkify: true,
        breaks: true,
        highlight: function (str, lang) {
          return `<pre class="hljs language-${lang}"><code class="language-${lang} ${lang}">${hljs.highlightAuto(str).value}</code></pre>`;
        }
      }).render(article.content);
      return {
        article,
        content,
      };
    } catch (err) {
      return false;
    }
  },
}

My content is fetched and rendered server side ;)

[iancleary]

I know this is closed, but in case anyone searches for it, I found Samuel Coe's article very useful 🎉

How to Use Markdown-It with Highlight.js in a Nuxt Project

[pi0]

(opened until adding to docs or built-in feature)