vite-node

Vite as Node runtime.
The engine that powers Vitest and Nuxt 3 Dev SSR.

Features#

• On-demand evaluation
• Vite's pipeline, plugins, resolve, aliasing
• Out-of-box ESM & TypeScript support
• Respect vite.config.ts
• Hot module replacement (HMR)
• Separate server/client architecture
• Top-level await
• Shims for __dirname and __filename in ESM
• Access to native node modules like fs, path, etc.

CLI Usage#

Run JS/TS file on Node.js using Vite's resolvers and transformers.

npx vite-node index.ts

Options:

npx vite-node -h

Options via CLI#

All ViteNodeServer options are supported by the CLI. They may be defined through the dot syntax, as shown below:

npx vite-node --options.deps.inline="module-name" --options.deps.external="/module-regexp/" index.ts

Note that for options supporting RegExps, strings passed to the CLI must start and end with a /;

Hashbang#

If you prefer to write scripts that don't need to be passed into Vite Node, you can declare it in the hashbang.

Simply add #!/usr/bin/env vite-node --script at the top of your file:

file.ts

#!/usr/bin/env vite-node --script

console.log('argv:', process.argv.slice(2))

And make the file executable:

chmod +x ./file.ts

Now, you can run the file without passing it into Vite Node:

$ ./file.ts hello
argv: [ 'hello' ]

Note that when using the --script option, Vite Node forwards every argument and option to the script to execute, even the one supported by Vite Node itself.

Programmatic Usage#

In Vite Node, the server and runner (client) are separated, so you can integrate them in different contexts (workers, cross-process, or remote) if needed. The demo below shows a simple example of having both (server and runner) running in the same context

import { createServer } from 'vite'
import { ViteNodeServer } from 'vite-node/server'
import { ViteNodeRunner } from 'vite-node/client'
import { installSourcemapsSupport } from 'vite-node/source-map'

// create vite server
const server = await createServer({
  optimizeDeps: {
    // It's recommended to disable deps optimization
    disabled: true,
  },
})
// this is need to initialize the plugins
await server.pluginContainer.buildStart({})

// create vite-node server
const node = new ViteNodeServer(server)

// fixes stacktraces in Errors
installSourcemapsSupport({
  getSourceMap: source => node.getSourceMap(source),
})

// create vite-node runner
const runner = new ViteNodeRunner({
  root: server.config.root,
  base: server.config.base,
  // when having the server and runner in a different context,
  // you will need to handle the communication between them
  // and pass to this function
  fetchModule(id) {
    return node.fetchModule(id)
  },
  resolveId(id, importer) {
    return node.resolveId(id, importer)
  },
})

// execute the file
await runner.executeFile('./example.ts')

// close the vite server
await server.close()

Debugging#

Debug Transformation#

Sometimes you might want to inspect the transformed code to investigate issues. You can set environment variable VITE_NODE_DEBUG_DUMP=true to let vite-node write the transformed result of each module under .vite-node/dump.

If you want to debug by modifying the dumped code, you can change the value of VITE_NODE_DEBUG_DUMP to load and search for the dumped files and use them for executing.

VITE_NODE_DEBUG_DUMP=load vite-node example.ts

Or programmatically:

import { ViteNodeServer } from 'vite-node/server'

const server = new ViteNodeServer(viteServer, {
  debug: {
    dumpModules: true,
    loadDumppedModules: true,
  },
})

Debug Execution#

If the process gets stuck, it might be because there are unresolvable circular dependencies. You can set VITE_NODE_DEBUG_RUNNER=true for vite-node to warn about this.

VITE_NODE_DEBUG_RUNNER=true vite-node example.ts

Or programmatically:

import { ViteNodeRunner } from 'vite-node/client'

const runner = new ViteNodeRunner({
  debug: true,
})

Credits#

Based on @pi0's brilliant idea of having a Vite server as the on-demand transforming service for Nuxt's Vite SSR.

Thanks @brillout for kindly sharing this package name.

Sponsors#

License#

MIT License © 2021 Anthony Fu