TypeError An error occurred. post.render is not a function

TLDR. The “post.render is not a function” error in Astro can be resolved by changing the output option in the astro.config.mjs file or by modifying the code in the dynamic route.

post.render is not a function

The “post.render is not a function” error in Astro occurs when the output option is set to server in the astro.config.mjs config file.

To solve the “post.render is not a function” error in Astro, there are two methods that can be employed.

1. Change the output: 'server' to output: 'static' in the astro.config.mjs config file.

import { defineConfig } from 'astro/config';
import mdx from '@astrojs/mdx';
import sitemap from '@astrojs/sitemap';

// https://astro.build/config
export default defineConfig({
	site: 'https://example.com',
	integrations: [mdx(), sitemap()],
-   output: 'server'
+   output: 'static'
});

2. Modify the getStaticPaths function in your dynamic route.

To resolve the issue, change the code in the dynamic route as follows:

For instance, if the file path is src\pages\blog\[...slug].astro, make the following changes:

- export async function getStaticPaths() {
- 	const posts = await getCollection('blog');
- 	return posts.map((post) => ({
- 		params: { slug: post.slug },
- 		props: post,
- 	}));
- }

+ const posts = await getCollection('blog');
+ const { slug } = Astro.params;
+ const post = posts.find((page) => page.slug === slug);
+ if (!post) return Astro.redirect("/404");

- const post = Astro.props;
const { Content } = await post.render();

References

Thanks to Jussi Norlund ¹

May 16, 2024