Dynamic route parameters in Remix - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What does this Remix route component render?

Given a dynamic route file named routes/posts/$postId.jsx in Remix, what will the component render if the URL is /posts/42?

Remix

import { useParams } from '@remix-run/react';

export default function Post() {
  const params = useParams();
  return <div>Post ID is {params.postId}</div>;
}

A Post ID is $postId

B Post ID is 42

C Post ID is undefined

D Error: useParams is not a function

💡 Hint

Remember that dynamic route parameters are available via useParams hook.

The dynamic segment $postId captures the URL part '42'. The useParams hook returns an object with keys matching dynamic segments, so params.postId is '42'.

📝 Syntax

intermediate

Which route file name correctly defines a dynamic parameter for user ID?

In Remix, which file name correctly creates a route with a dynamic parameter named userId?

A routes/users/:userId.jsx

B routes/users/[userId].jsx

C routes/users/$userId.jsx

D routes/users/userId.jsx

💡 Hint

Remix uses a special prefix for dynamic segments in file names.

Remix uses the $ prefix to mark dynamic route segments. So $userId.jsx defines a dynamic parameter named userId.

❓ state_output

advanced

What is the value of params in nested dynamic routes?

Consider the nested route files routes/blog/$category/$postId.jsx. If the URL is /blog/tech/123, what is the value of params from useParams() inside the component?

Remix

import { useParams } from '@remix-run/react';

export default function Post() {
  const params = useParams();
  return <div>{JSON.stringify(params)}</div>;
}

A {"category":"tech","postId":"123"}

B {"category":"blog","postId":"tech"}

C {"postId":"123"}

D {}

💡 Hint

All dynamic segments in the route path are included in params.

The params object includes all dynamic segments from the route path. Here, category is 'tech' and postId is '123'.

🔧 Debug

advanced

Why does this dynamic route component fail to get the parameter?

Given the route file routes/products/$productId.jsx and this component code, why does params.productId return undefined?

Remix

import { useParams } from '@remix-run/react';

export default function Product() {
  const params = useParams;
  return <div>Product: {params.productId}</div>;
}

A The dynamic segment should be named $productID with uppercase D.

B useParams hook only works in server components, not client components.

C The route file name must be $productId.tsx, not .jsx.

D useParams is not called as a function, so params is the function itself, not the params object.

💡 Hint

Check how useParams is used in the code.

The code assigns useParams without calling it. It should be const params = useParams(); to get the params object.

🧠 Conceptual

expert

How does Remix handle optional dynamic route parameters?

Which statement correctly describes how Remix supports optional dynamic route parameters in file naming and routing?

A Remix does not support optional dynamic parameters directly; you must create separate routes for each case.

B You can add a question mark after the parameter name in the file like $id?.jsx to make it optional.

C Optional parameters are defined by prefixing the file name with an underscore like _$id.jsx.

D Remix supports optional parameters by wrapping the dynamic segment in parentheses like ( $id ).jsx.

💡 Hint

Think about how Remix routing matches files to URLs.

Remix routing does not have built-in syntax for optional dynamic parameters. You create separate routes for the optional and non-optional cases.