How to pass command line arguments to Deno? - command-line-arguments

Question

I have a Deno app, that I wish to pass some command line args to. I searched the manual, but found nothing.
I tried to use the same commands used in Node.js, assuming they might be sharing some for the std libraries, but it didn't work as well.
var args = process.argv.slice(2);
// Uncaught ReferenceError: process is not defined
Any suggestions?

Answer 1

You can access arguments by using Deno.args, it will contain an array of the arguments passed to that script.
// deno run args.js one two three
console.log(Deno.args); // ['one, 'two', 'three']
If you want to parse those arguments you can use std/flags, which will parse the arguments similar to minimist
import { parse } from "https://deno.land/std/flags/mod.ts";
console.log(parse(Deno.args))
If you call it with:
deno run args.js -h 1 -w on
You'll get
{ _: [], h: 1, w: "on" }

Answer 2

You can use Deno.args to access the command line arguments in Deno.
To try it create a file test.ts :
console.log(Deno.args);
And run it with deno run test.ts firstArgument secondArgument
It will return you with an array of the passed args:
$ deno run test.ts firstArgument secondArgument
[ "firstArgument", "secondArgument" ]

Answer 3

If you take a stroll through the standard library, you will find a library named flags, which sounds like it could be library for command line parsing. In the README, you will find your answer in the very first line:
const { args } = Deno;
Also, if you look at the Deno Manual, specifically the Examples section, you will find numerous examples of command line example programs that perform argument parsing, for example, a clone of the Unix cat command (which is also included in the First Steps section of the Deno Manual), where you will also find your answer in the first line:
for (let i = 0; i < Deno.args.length; i++)
So, in short: the command line arguments are a property of the global Deno object, which is documented here:
const Deno.args: string[]
Returns the script arguments to the program. If for example we run a program:
deno run --allow-read https://deno.land/std/examples/cat.ts /etc/passwd
Then Deno.args will contain:
[ "/etc/passwd" ]
Note: According to the Manual, all non-web APIs are under the global Deno namespace.