Flags

Command line arguments parser with build-in validations.

Usage

The parseFlags method accepts as first argument the arguments that to be parsed, usually Deno.args. As the second argument you can pass an options object. A list of all available options can be found here.

Basic usage

If parseFlags is called without defining specific flags with the options object, all flags passed as first arguments to the parseFlags method are parsed and added to the flags object returned by the parseFlags method. All non-options arguments are added to the unknown array and all flags specified after the double dash (--) are added to the literal array.

import { parseFlags } from "https://deno.land/x/cliffy@v0.25.0/flags/mod.ts";

console.log(parseFlags(Deno.args));Copy

$ deno run https://deno.land/x/cliffy@v0.25.0/examples/flags/flags.ts -a foo -b bar
{ flags: { a: "foo", b: "bar" }, unknown: [], literal: [] }

$ deno run https://deno.land/x/cliffy@v0.25.0/examples/flags/flags.ts \
    -x 3 \
    -y.z -n5 \
    -abc \
    --beep=boop \
    foo bar baz \
    --deno.land \
    --deno.com -- --cliffy
{
  flags: {
    x: "3",
    y: { z: true },
    n: "5",
    a: true,
    b: true,
    c: true,
    beep: "boop",
    deno: { land: true, com: true }
  },
  unknown: [ "foo", "bar", "baz" ],
  literal: [ "--cliffy" ]
}Copy

Flags

You can specify flagswith the options object. For all unknown or invalid flags an ValidationError is thrown. Read more about error handling here. A list of all available flag options can be found here.

import { parseFlags } from "https://deno.land/x/cliffy@v0.25.0/flags/mod.ts";

const { flags } = parseFlags(Deno.args, {
  flags: [{
    name: "help",
    aliases: ["h"],
    standalone: true,
  }, {
    name: "verbose",
    aliases: ["v"],
    collect: true,
    value: (val: boolean, previous = 0) => val ? previous + 1 : 0,
  }, {
    name: "file",
    aliases: ["f"],
    type: "string",
  }],
});

console.log(flags);Copy

$ deno run https://deno.land/x/cliffy@v0.25.0/examples/flags/options.ts -vvv -f ./example.ts
{ verbose: 3, file: "./example.ts" }Copy

← Others Parse options →

Edit this page on GitHub