Fix: Missing Params Property on getStaticPaths Route in Astro

What Causes This Error?

This error occurs when an entry returned from getStaticPaths() is missing the required params property. Each entry must have a params object containing values for all dynamic route segments.

The Problem

---
// src/pages/blog/[slug].astro
export function getStaticPaths() {
  return [
    // ❌ Missing params property
    { slug: 'post-1' },
    { slug: 'post-2' },
  ];
}
---

---
export function getStaticPaths() {
  return [
    // ❌ params is null/undefined
    { params: null },
    { params: undefined },
  ];
}
---

The Fix

Add Params Property

---
// src/pages/blog/[slug].astro
export function getStaticPaths() {
  return [
    // ✅ Wrap in params object
    { params: { slug: 'post-1' } },
    { params: { slug: 'post-2' } },
  ];
}
---

With Props

---
export function getStaticPaths() {
  return [
    {
      params: { slug: 'post-1' },
      props: { title: 'First Post' }
    },
    {
      params: { slug: 'post-2' },
      props: { title: 'Second Post' }
    },
  ];
}

const { slug } = Astro.params;
const { title } = Astro.props;
---

Common Scenarios

Mapping Data Incorrectly

---
const posts = [
  { slug: 'post-1', title: 'First' },
  { slug: 'post-2', title: 'Second' },
];

// ❌ Wrong - returns the post object directly
export function getStaticPaths() {
  return posts;
}

// ✅ Correct - wrap in params
export function getStaticPaths() {
  return posts.map((post) => ({
    params: { slug: post.slug },
    props: { title: post.title },
  }));
}
---

Content Collections

---
import { getCollection } from 'astro:content';

export async function getStaticPaths() {
  const entries = await getCollection('blog');

  // ✅ Map to correct structure
  return entries.map((entry) => ({
    params: { slug: entry.slug },
    props: { entry },
  }));
}
---

Multiple Parameters

---
// src/pages/[lang]/blog/[slug].astro
export function getStaticPaths() {
  const posts = ['intro', 'advanced'];
  const langs = ['en', 'es'];

  // ✅ All params must be included
  return langs.flatMap((lang) =>
    posts.map((slug) => ({
      params: { lang, slug },
    }))
  );
}
---

Rest Parameters

---
// src/pages/docs/[...path].astro
export function getStaticPaths() {
  return [
    { params: { path: 'intro' } },
    { params: { path: 'guide/basics' } },
    { params: { path: undefined } }, // ✅ Matches /docs/
  ];
}
---

Quick Checklist

• Each entry needs { params: { ... } } structure
• All dynamic segments must be in params
• Use .map() to transform data arrays
• Params values must be strings, numbers, or undefined
• Props are optional but params are required