Examples of how to run modules in the Deno standard library.

Deno also provides a list of audited standard modules that are reviewed by the core Deno team and are guaranteed to work with a specific Deno version. source

See denoland/deno repository for source code of Deno and standard lib.

These are hosted at deno.land/std.

Welcome

Run this package directly in the shell - no script needed.

$ deno run https://deno.land/std/examples/welcome.ts

File server

Using std/http/file_server.ts:

$ deno run --allow-read --allow-net https://deno.land/std/http/file_server.ts

Or write a more complex one using http/server.ts:

  • index.ts 
      import { serve } from "https://deno.land/std@0.59.0/http/server.ts";

  const s = serve({ port: 8000 });

  console.log("http://localhost:8000/");

  for await (const req of s) {
    req.respond({ body: "Hello World\n" });
  }

Start the server with necessary permissions.

$ deno run --allow-read --allow-net index.ts

Flags

From the Flags documentation.

import { parse } from "https://deno.land/std@$STD_VERSION/flags/mod.ts";

console.dir(parse(Deno.args));

$ deno run https://deno.land/std/examples/flags.ts -a beep -b boop
{ _: [], a: 'beep', b: 'boop' }

$ deno run https://deno.land/std/examples/flags.ts -x 3 -y 4 -n5 -abc --beep=boop foo bar baz
{ _: [ 'foo', 'bar', 'baz' ],
  x: 3,
  y: 4,
  n: 5,
  a: true,
  b: true,
  c: true,
  beep: 'boop' }

Argument parsing

Using this command:

$ deno run index.ts --foo bar

The arguments are just an array. Which is not so easy to work with.

const args = Deno.args
// ["--foo", "bar"]

We can use parse from the standard library to convert to key-value pairs.

import { parse } from "https://deno.land/std@0.84.0/flags/mod.ts";

const args = parse(Deno.args);
// { foo: "bar" }