vercel-deno
v3.1.1
Published
Vercel Runtime for Deno serverless functions
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The Deno Runtime compiles a TypeScript or JavaScript function into a serverless function powered by Deno, running on Vercel.
⚠️ Version 3 includes breaking changes! ⚠️
Please read the migration guide.
Usage
Your serverless function file is expected to export default
the HTTP handler
function, and then vercel-deno
takes care of invoking that handler function
every time an HTTP request is received.
Note: Check out the
api
directory to see examples of using popular Deno web frameworks withvercel-deno
. Feel free to send a pull request to add additional examples!
Example
Create a file called api/hello.ts
with the following contents:
export default (req: Request) => {
return new Response(`Hello, from Deno v${Deno.version.deno}!`);
};
Next, define the vercel-deno runtime within the "functions" object in your
vercel.json
file:
{
"functions": {
"api/**/*.[jt]s": { "runtime": "[email protected]" }
}
}
Demo: https://vercel-deno.vercel.app/api/hello
Configuration
To configure which flags are passed to deno run
, a shebang needs to be defined in
the entrypoint of the Serverless Function containing the flags that will be used.
For example, to set the window.location
object, and use a specific tsconfig file:
#!/usr/bin/env deno run --location http://example.com/path --config other-tsconfig.json
export default async () => new Response(`Location is ${window.location.href}!`);
There are also a few flags that can be used that are specific to vercel-deno
:
--version
- Specify a specific version of Deno to use (can be any valid Deno release tag — e.g.v1.2.3
).--include-files
- Glob pattern of static files to include within the Serverless Function. Can be specified more than once.
Endpoint-specific Environment Variables
It's also possible to specify environment variables that will apply only to a specific API endpoint by utilizing the shebang. Just place the environment variables before the deno
command in the shebang. For example:
#!/usr/bin/env FOO=bar ANOTHER="spaces work too" deno run
In this example, the FOO
environment variable will be set to "bar" and ANOTHER
will be set to "spaces work too" for only this endpoint.
Dynamic Imports
By default, dynamic imports (using the import()
function during runtime) will fail. For most use-cases, this is fine since this feature is only necessary for rare use-cases.
However, when dynamic imports are required for your endpoint, the DENO_DIR
environment variable will need to be set to "/tmp". This is required because the file system is read-only, within the Serverless Function runtime environment, except for the "/tmp" dir. Because dynamic imports will require compilation at runtime, the deno cache directory needs to be writable.
The recommended way of enabling this is to add an environment variable to the endpoint's shebang. For example:
#!/usr/bin/env DENO_DIR=/tmp deno run
export default async () => {
const mod = await import('http://example.com/mod.ts');
return new Response(mod.default.doThing());
};
Development
The vercel dev
command is supported on Windows, macOS, and Linux:
- Vercel CLI v19.1.0 or newer is required.
- Uses the
deno
binary installed on the system (does not downloaddeno
). - Specifying a specific version of Deno via
--version
flag is ignored.