A folk version of the urlcat focuses on performance and simplicity. Build correct URLs easily. A fast, minimal fork of urlcat focused on performance and simplicity.
fast-url is a tiny JavaScript/TypeScript library that makes building URLs convenient and prevents common mistakes.
- Lightweight: Only one dependency (fast-querystring) and minimal bundle size
- Type safe: Written in TypeScript with full type definitions
- URL safe: Automatically escapes parameters and handles edge cases
- Flexible: Multiple ways to build URLs for different use cases
# Using bun (recommended)
bun add fast-url
# Using npm
npm install fast-url
import urlcat from "fast-url";
// Path parameters
urlcat("https://api.example.com", "/users/:id", { id: 123 });
// → 'https://api.example.com/users/123'
// Query parameters
urlcat("https://api.example.com", "/users", { limit: 10, offset: 20 });
// → 'https://api.example.com/users?limit=10&offset=20'
// Combined path and query parameters
urlcat("https://api.example.com", "/users/:id/posts", { id: 123, limit: 10 });
// → 'https://api.example.com/users/123/posts?limit=10'const urlcat = require("fast-url").default;import { query, subst, join } from "fast-url";
// Build query strings
query({ name: "John", age: 30 });
// → 'name=John&age=30'
// Substitute path parameters
subst("/users/:id/posts/:postId", { id: 123, postId: 456 });
// → '/users/123/posts/456'
// Join URL parts
join("https://api.example.com/", "/", "/users");
// → 'https://api.example.com/users'Build a complete URL by combining a base URL, path template, and parameters.
Use a single template containing path parameters; unused params become query parameters.
Build a query string from an object of key-value pairs.
Substitute path parameters in a template string.
Join two URL parts with exactly one separator.
Building URLs manually is error-prone:
// ❌ Error-prone manual approach
const url = `${baseUrl}/users/${id}/posts?limit=${limit}&offset=${offset}`;
// Issues: double slashes, unescaped parameters, complex concatenation// ✅ Clean and safe with fast-url
const url = urlcat(baseUrl, "/users/:id/posts", { id, limit, offset });fast-url handles:
- Automatic parameter escaping
- Proper URL segment joining
- Clean separation of path and query parameters
Contributions are welcome! Please feel free to submit a Pull Request.
MIT