CORS middleware for Micro

Summary

Simple CORS middleware for Zeit's Micro

We're working on v1, come help us out!

Install

yarn add micro-cors

Usage

Basic:

const { send } = require('micro')
const cors = require('micro-cors')()

const handler = (req, res) => send(res, 200, 'ok!')

module.exports = cors(handler)

With options:

const { send } = require('micro')
const microCors = require('micro-cors')
const cors = microCors({ allowMethods: ['PUT', 'POST'] })

const handler = (req, res) => send(res, 200, 'ok!')

module.exports = cors(handler)

Since the current version of micro-cors only sets headers in the response (res), you have do some manual work if you want to avoid triggering your handler on an OPTIONS preflight request (this will be built-in in v1). Let's say you want to approve preflight requests and otherwise only let POST requests trigger the handler:

const { send } = require('micro')
const cors = require('micro-cors')()

const handler = (req, res) => {
  if (req.method === 'OPTIONS') {
    return send(res, 200, 'ok!');
  }

  if (req.method !== 'POST') {
    throw createError(404, 'Not Found');
  }

  // handle incoming request as usual
}

module.exports = cors(handler)

Options

allowMethods

default: ['POST','GET','PUT','PATCH','DELETE','OPTIONS']

allowHeaders

default: ['X-Requested-With','Access-Control-Allow-Origin','X-HTTP-Method-Override','Content-Type','Authorization','Accept']

allowCredentials

default: true

exposeHeaders

default: []

maxAge

default: 86400

origin

default: *