Quick overview
Installation
The Edge Runtime is available as Node.js package. You can install it with your favorite package manager:
npm install edge-runtime
Usage
Once it's installed, you can evaluate any script into the runtime context:
import { EdgeRuntime } from 'edge-runtime'
const runtime = new EdgeRuntime()
const result = await runtime.evaluate("fetch('https://example.com')")
console.log(result)
The runtime provides you with ready to use Web APIs that can be extended if needed:
import { EdgeRuntime } from 'edge-runtime'
const runtime = new EdgeRuntime({
extend: (context) => {
const rawFetch = context.fetch.bind(context.fetch)
context.fetch = async (input: RequestInfo | URL, init?: RequestInit) =>
rawFetch(
typeof input === 'string' && !input.startsWith('https://')
? `https://${input}`
: String(input),
init
)
return context
},
})
const result = await runtime.evaluate("fetch('example.com')")
console.log(result)
You can also load some initial code and interact with it as a regular HTTP server:
import { EdgeRuntime } from 'edge-runtime'
const initialCode = `
addEventListener('fetch', event => {
const { searchParams } = new URL(event.request.url)
const url = searchParams.get('url')
return event.respondWith(fetch(url))
})`
const edgeRuntime = new EdgeRuntime({ initialCode })
const response = await edgeRuntime.dispatchFetch('https://example.com')
// If your code logic performs asynchronous tasks, you should await them.
// https://developer.mozilla.org/en-US/docs/Web/API/ExtendableEvent/waitUntil
await response.waitUntil()
To expose the server:
import { EdgeRuntime, runServer } from 'edge-runtime'
import exitHook from 'exit-hook'
import fetch from 'node-fetch'
const initialCode = `
addEventListener('fetch', event => {
const { searchParams } = new URL(event.request.url)
const url = searchParams.get('url')
return event.respondWith(fetch(url))
})`
const edgeRuntime = new EdgeRuntime({ initialCode })
const server = await runServer({ runtime: edgeRuntime })
exitHook(server.close)
const response = await fetch(server.url)