Yargs not working when using import in Node.js

Question

I'm new to Node.js and I'm learning some basics now. I'm trying to use some typescript code to convert into .js code later.

I wrote this simple code to test

    import * as fs from 'fs'


    const argv = require('yargs')
                .alias('f', 'filename')
                .alias('c', 'content')
                .demandOption('filename')
                .demandOption('content')
                .argv

    fs.writeFile(argv.filename, argv.content, (error)=>{
        if(error) 
            throw error
        console.log(`File ${argv.filename} saved.`)
    })

And this works fine. But when I change the line require('yargs') to import, like below:

   import * as fs from 'fs'
   import * as yargs from 'yargs'

    const argv = yargs
                .alias('f', 'filename')
                .alias('c', 'content')
                .demandOption('filename')
                .demandOption('content')
                .argv

    fs.writeFile(argv.filename, argv.content, (error)=>{
        if(error) 
            throw error
        console.log(`File ${argv.filename} saved.`)
    })

I'm getting this error:

Argument of type 'unknown' is not assignable to parameter of type 'string | number | Buffer | URL'.

Type '{}' is missing the following properties from type 'URL': hash, host, hostname, href, and 9 more.ts(2345)

Does anybody know what's the difference between using module/import that is causing this error? For fs library both ways work fine in this example.

"in ES6, yargs is no longer a singleton, so you need to call yargs() to get an instance of yargs, at which point the API is identical, here's a simple example:" github.com/yargs/yargs/issues/1854 — loop
– loop, Commented Dec 25, 2021 at 17:39

loop · Accepted Answer · 2021-12-25 18:00:02Z

12

Here is the corrected code for anyone still wondering how to use ES6 module syntax with Yargs. I had to add some type information with option() to avoid errors. Refer to a Github discussion for more information.

import fs from 'fs';
import _yargs from 'yargs';
import { hideBin } from 'yargs/helpers';
const yargs = _yargs(hideBin(process.argv));

(async () => {
    const argv = await yargs
        .option('filename', { type: 'string', require: true })
        .option('content', { type: 'string', require: true })
        .alias('f', 'filename')
        .alias('c', 'content')
        .argv;

    fs.writeFile(argv.filename, '' + argv.content, error => {
        if (error) throw error;
        console.log(`File ${argv.filename} saved.`);
    });
})();

answered Dec 25, 2021 at 18:00

loop

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2 Comments

j3g Over a year ago

this has all the correct parts for me to get past my error, I compared to what I was trying to do and fixed. I converted const yargs = require('yargs/yargs') to import yargs from 'yargs/yargs'; which throws an error.

Mark Over a year ago

If you don't like the _ naming convention, I find yargsFactory is a good name for this.

kepung · Accepted Answer · 2021-04-06 09:17:11Z

3

Have you tried installing yargs typings, by running the following command?

npm install --save @types/yargs

answered Apr 6, 2021 at 9:17

kepung

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Comments

user12421871 · Accepted Answer · 2021-04-03 23:36:57Z

1

I think ES6 compliant import is still not supported and only require works.

import yargs from 'yargs'
console.log(yargs.argv)

$ node app.js
undefined

answered Apr 3, 2021 at 23:36

user12421871

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1 Comment

jeiea Over a year ago

Why not console.log(yargs)?

0Valt · Accepted Answer · 2021-05-27 03:18:58Z

0

You need to set the type of args from argv. Try to change your core to:

const argv = yargs
        .option('filename', {
            alias: 'f',
            demandOption: true,
            describe: 'Nome do arquivo',
            type: 'string'
        })
        .option('content', {
            alias: 'c',
            demandOption: true,
            describe: 'Conteudo',
            type: 'string'
        })
        .argv

edited May 27, 2021 at 3:18

0Valt

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answered Apr 17, 2020 at 21:50

fcfeitosa

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1 Comment

0Valt Over a year ago

Please do not use code snippets for scripts that cannot be run without external dependencies or platforms. Use proper code formatting [Ctrl+K] instead: single backticks (“`”) for one-liners, property names and methods, code fences (“````”) for code blocks. Also please avoid chit-chat in questions, SO is not a forum, it is a Q&A website.

Tamaro Tamaroidny · Accepted Answer · 2023-08-16 16:14:48Z

0

i found this solution to use Yargs with module type

import yargs from 'yargs/yargs';  // (v17.7.2)

const argv = yargs(process.argv.slice(2))
    .option('dev', {
        alias: 'd',
        type: 'boolean',
        describe: 'dev mode'
    })
    .argv;

console.log(argv.dev); // will be true when starting "node index.js --dev"

source for typescript, usable in NodeJS with "type": "module" https://github.com/yargs/yargs/blob/main/docs/typescript.md

answered Aug 16, 2023 at 16:14

Tamaro Tamaroidny

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