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.

Refer https://www.typescriptlang.org/docs/handbook/modules.html — Sudhakar Ramasamy, Oct 07 '19 at 15:52
"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:" https://github.com/yargs/yargs/issues/1854 — loop, Dec 25 '21 at 17:39

score 4 · Answer 1 · answered Dec 25 '21 at 18:00

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.`);
    });
})();

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. — j3g, Mar 17 '22 at 23:22

score 2 · Answer 2 · answered Apr 06 '21 at 09:17

2

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

npm install --save @types/yargs

answered Apr 06 '21 at 09:17

kepung

2,102
2
22
24

score 1 · Answer 3 · answered Apr 03 '21 at 23:36

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 03 '21 at 23:36

user12421871

11
1

Why not `console.log(yargs)`? – jeiea Apr 04 '21 at 00:55

score 0 · Answer 4 · edited May 27 '21 at 03:18

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 '21 at 03:18

Oleg Valter is with Ukraine

9,619
8
37
59

answered Apr 17 '20 at 21:50

fcfeitosa

63
6

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. – Oleg Valter is with Ukraine May 27 '21 at 03:19

score 0 · Answer 5 · answered Aug 16 '23 at 16:14

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

Yargs not working when using import in Node.js

5 Answers5