nitro Cross-Origin Resource Sharing (CORS) Headers

nitro native CORS event handler.

Requirements

• nitro v.2.6.* or higher

Installation

npm install nitro-cors

pnpm add nitro-cors

yarn add nitro-cors

Usage

nitro CORS is built upon the h3 CORS utilities provided by the h3 library. To read more about h3's inbuilt cors library, please consult the h3 repository.

To get started, you can enable CORS on a specific event handler by using the object syntax definitions intorduced in nitro v2.6.0 and h3 v1.8.0 as follows:

import { cors } from 'nitro-cors'

export default eventHandler({
  onRequest: [
    cors({
      origin: '*',
      methods: '*'
      // ... add your options overrides here
    })
  ],
  async handler(event) {
    return 'Hello CORS!'
  }
})

nitro-cors also provides a simple wrapper to define a CORS event handler per nitro event handler, or per route. To use it, simply import the defineCORSEventHandler function and wrap your event handler with it as follows:

import { defineCORSEventHandler } from 'nitro-cors'

const handler = eventHandler(async event => {
  // ...
})

export default defineCORSEventHandler(handler, {
  origin: '*',
  methods: '*'
})

...or... using as nitro middleware:

// :file middleware/cors.ts
import { corsEventHandler } from 'nitro-cors'

export default corsEventHandler(_event => {}, {
  origin: '*',
  methods: '*'
})

The defineCORSEventHandler and corsEventHandler functions take two arguments:

• handler: the event handler to wrap of type EventHandler<T>, which will ensure typesafety for the event handler return type.
• options: the options to pass to the cors handler of type H3CorsOptions. These are the same options as the ones passed to the h3 cors library.

Options

The options passed to the cors handler are the same as the ones passed to the h3 cors library. Please consult the h3 repository

Acknowledgements

This library would not be possible if it were not for standing on the shoulders of these giants:

• h3