tylerpillay

Welcome back! In Part 1 we got our SvelteKit project set up and installed all the tools we’ll need to get going. This time we’re going to render a markdown file as a blog post with the help of Mdsvex. A lot of this post will be similar to parts of JoyOfCode’s post, so if you want more details, check out his post.

Let’s jump in!

Create a post using markdown

Create a directory called posts in the src directory. Inside src/posts create a file called hello-world.md.

---
title: Hello World
description: My hello world post!
date: '2023-05-19'
tags:
  - svelte
  - daisyui
  - tailwindcss
  - mdsvex
published: true # this will be used to filter out unpublished posts
---

## Hello World

This is my first post!

Add typing (skip this if you’re using JS)

Create a file to store your types in src/lib/types/. I just called mine index.ts. In src/lib/types/index.ts add the following:

export type Post = {
	title: string
	slug: string
	description: string
	date: string
	tags: string[]
	published: boolean
}

Create an API endpoint to get our posts

Create a +server.ts file in src/routes/api/posts/. This will be used to get all of our posts, so we can render a list of them on the home page.

import { json } from '@sveltejs/kit';
import type { Post } from '$lib/types';
import { dev } from '$app/environment';

async function getPosts() {
	let posts: Post[] = [];

	const paths = import.meta.glob('/src/posts/*.md', { eager: true });

	for (const path in paths) {
		const file = paths[path];
		const slug = path.split('/').at(-1)?.replace('.md', '');

		if (file && typeof file === 'object' && 'metadata' in file && slug) {
			const metadata = file.metadata as Omit<Post, 'slug'>;
			const post = { ...metadata, slug } satisfies Post;

			// only add posts to the array if we're in dev mode or if the post is published
			// this will allow us to preview posts (if publised is false in the .md file) locally before publishing them
			dev && posts.push(post) || post.published && posts.push(post);
		}
	}

	posts = posts.sort((first, second) => new Date(second.date).getTime() - new Date(first.date).getTime());

	return posts;
}

export async function GET() {
	const posts = await getPosts();
	return json(posts);
}

What’s going on here?

We’re using import.meta.glob which is a Vite feature that lets us get all the posts using a glob and eager lets us read the file contents without having to await.
We loop over the paths to get the slug (file name) and then we drop the .md extension.
We check if the file is an object and has a metadata property. If it does, we destructure the metadata and create a new post object with the slug and metadata and push it to the posts array (if they are published or we are developing locally).
Finally, we sort the posts by date and return them.

Sweet! Now we can retrieve all of our posts from the API endpoint.

Create a page to render our posts

Before we continue, let’s create a utility function to format the date in our posts. Add the following to src/lib/utils/index.ts:

type DateStyle = Intl.DateTimeFormatOptions['dateStyle']

export function formatDate(date: string, dateStyle: DateStyle = 'medium', locales = 'en') {
	const formatter = new Intl.DateTimeFormat(locales, { dateStyle })
	return formatter.format(new Date(date))
}

Create a +page.ts file in src/routes/. We’ll define a load function to call our endpoint and then pass the posts to our page.

import type { Post } from '$lib/types'

export async function load({ fetch }) {
	const response = await fetch('api/posts')
	const posts: Post[] = await response.json()
	return { posts }
}

Now in src/routes/+page.svelte we can loop over the posts from the load function and display them: We can access the posts via the data variable we export in the page. (This is built into SvleteKit, how cool!)

<script lang="ts">
	import { formatDate } from '$lib/utils'

	export let data
</script>

<svelte:head>
    <title>Home</title>
</svelte:head>

<section>
    {#each data.posts as post}
        <a href={post.slug} class="flex flex-col cursor-pointer rounded-box p-2 sm:p-4 sm:my-1 hover:underline">
            <p class='font-bold text-2xl'>{post.title}</p>
            <p class='text-md'>{post.description}</p>
            <p class='italic pt-1 text-sm'>{formatDate(post.date)}</p>
        </a>
        <div class='divider'></div>
    {/each}
</section>

You should now be able to see your post rendered on the page!

Render a single post

Create a routes/[slug]/+page.ts file. This will be used to render a single post.

import { error } from '@sveltejs/kit'

export async function load({ params }) {
	try {
		const post = await import(`../../posts/${params.slug}.md`)

		return {
			content: post.default,
			meta: post.metadata
		}
	} catch (e) {
		throw error(404, `Could not find ${params.slug}`)
	}
}

We use a dynamic import to get the post and then return the content and metadata from the post. If the post doesn’t exist, we throw a 404 error.

Now in routes/[slug]/+page.svelte we can render the post:

<script lang="ts">
    import {formatDate} from '$lib/utils'

    export let data
</script>

<article>
    <hgroup class="flex flex-col">
        <h1 class='text-2xl font-bold mb-1'>{data.meta.title}</h1>
        <p class='italic text-sm mb-4'>Published on {formatDate(data.meta.date)}</p>
    </hgroup>

    <div class='my-2 flex flex-wrap'>
        {#each data.meta.tags as tag}
            <span class="mx-0.5 p-2 border-2 rounded-2xl text-xs font-semibold cursor-pointer">&num;{tag}</span>
        {/each}
    </div>

    <div class='divider'></div>

    <!-- The prose class is from Tailwind Typography so we don't need to define -->
    <div class="prose">
        <svelte:component this={data.content}/>
    </div>
</article>

We can use a Svelte component to pass data.content to <svelte:component this={data.content} /> because the markdown file is imported as a module and processed by mdsvex.

You should now be able to see your post rendered from the markdown on your page!

Repo

SvelteKitxMdsvex