README.md

vercel-cors

A simple CORS module for use with Vercel Serverless Functions. Also compatible with Next.js API Routes.

Installation

yarn add vercel-cors | npm i vercel-cors

Usage

Create your CORS configuration in a separated file:

config/cors.js

import cors from "vercel-cors"

export default cors({
  origin: '*' | string | RegExp | Array<string | RegExp>,
  headers: string[],
  methods: Array<'GET' | 'HEAD' | 'POST' | 'PUT' | 'PATCH' | 'UPDATE' | 'DELETE' | 'OPTIONS'>,
  expose: string[],
  maxAge: number | undefined,
  credentials: boolean
})

Then export as default a Higher Order Function passing your handler as parameter:

api/index.js

import withCors from "config/cors"

async function handler (req, res) {
  // do something
}

export default withCors(handler)

Default options

export const defaults = {
  origin: '*',
  headers: ['Origin', 'X-Requested-With', 'Content-Type', 'Accept'],
  methods: ['GET', 'HEAD', 'POST', 'PUT', 'PATCH', 'UPDATE', 'OPTIONS', 'DELETE'],
  expose: [],
  maxAge: undefined,
  credentials: false
}

Example

import cors from "vercel-cors"

export default cors({
  origin: /^https:\/\/vercelproject-[a-z0-9]+-organization.vercel.app$/,
  methods: ['GET', 'POST', 'PUT', 'PATCH', 'UPDATE', 'DELETE'],
  credentials: true
})

Multiple configurations

Just export differents cors() functions from differents files:

config/cors
├── dev.js
└── prod.js

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diegoulloao · 2022