How to parse commandline args with yargs in typescript

Question

Here is what I tried (code adapted the code from the example in the yargs github readme):

// main.ts

import {Argv} from "yargs";


console.info(`CLI starter.`);

function serve(port: string) {
    console.info(`Serve on port ${port}.`);
}

require('yargs')
    .command('serve', "Start the server.", (yargs: Argv) => {
        yargs.option('port', {
            describe: "Port to bind on",
            default: "5000",
        }).option('verbose', {
            alias: 'v',
            default: false,
        })
    }, (args: any) => {
        if (args.verbose) {
            console.info("Starting the server...");
        }
        serve(args.port);
    }).argv;

Results:

npm run-script build; node build/main.js --port=432 --verbose

> [email protected] build /Users/kaiyin/WebstormProjects/typescript-cli-starter
> tsc -p .

CLI starter.

Looks like yargs has no effects here.

Any idea how to get this to work?

Damn. I adapted from the official example: github.com/yargs/yargs#complex-example — qed
– qed, Commented Jul 13, 2017 at 10:17

Peter Lamberg · Accepted Answer · 2020-07-24 14:12:55Z

14

I adapted the code from the example in the yargs github readme, turns out it's not meant to be a complete example. ¯_(ツ)_/¯

Anyways, I figured out how to do it:

#!/usr/bin/env node

import yargs, {Argv} from "yargs";

let argv = yargs
    .command('serve', "Start the server.", (yargs: Argv) => {
        return yargs.option('port', {
            describe: "Port to bind on",
            default: "5000",
        }).option('verbose', {
            alias: 'v',
            default: false,
        })
    }).argv;

if (argv.verbose) {
    console.info("Verbose mode on.");
}

serve(argv.port);

function serve(port: string) {
    console.info(`Serve on port ${port}.`);
}

You can find the complete typescript-cli-starter repo here: https://github.com/kindlychung/typescript-cli-starter

edited Jul 24, 2020 at 14:12

Peter Lamberg

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answered Jul 13, 2017 at 10:19

qed

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5 Comments

E_net4 Over a year ago

You are still importing 'yargs' twice. Consider doing let argv = yargs.command(...) ...

qed Over a year ago

Yep, now fixed.

Peter Lamberg Over a year ago

I tested with new versions of stuff and edited the answer accordingly. With the * as yargs form of import I was getting the error cannot redefine property: default. (Adding the error here in case somebody else is googling for that error and yargs). The correct way is to import the default export of yargs with import yargs from "yargs".

Roman Scher Over a year ago

Had to remove the return statement under the .command function to satisfy the typechecker, otherwise got a "No overload matches this call" type error. After that worked great!

Roman Scher Over a year ago

After updating something, not sure what, the typechecker got angry if I didn't use the ArgumentsCamelCase type in my .command callback function definition when destructuring the arguments, so had to specify it like ({ port }: ArgumentsCamelCase<{ port: string }>) => {}

Wouter van Nifterick · Accepted Answer · 2023-08-30 12:14:41Z

7

a minimalistic example

import * as yargs from 'yargs'

    let args = yargs
        .option('input', {
            alias: 'i',
            demandOption: true
        })
        .option('year', {
            alias: 'y',
            description: "Year number",
            demandOption: true
        }).argv;

    console.log(JSON.stringify(args));

edited Aug 30, 2023 at 12:14

Wouter van Nifterick

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answered Sep 25, 2018 at 17:42

Andrey

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Comments

Dmitriy Botov · Accepted Answer · 2023-03-06 13:41:22Z

4

An example including a command and callback function:

import yargs, { Argv, ArgumentsCamelCase } from 'yargs'
import { hideBin } from 'yargs/helpers'

yargs(hideBin(process.argv))
    .command(
        'select <color>',
        'Select a color to display',
        (args: Argv) => {
            args.positional('color', {
                describe: 'The color to display. e.g.) Blue to display blue'
            })
        },
        ({ color }: ArgumentsCamelCase<{ color: string }>) => {
            console.log(`Your color is ${color}!`)
        }
    )
    .demandCommand()
    .parse()

edited Mar 6, 2023 at 13:41

Dmitriy Botov

2,6611 gold badge17 silver badges13 bronze badges

answered Jul 27, 2022 at 15:29

Roman Scher

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