Yargs not working when using import in Node.js

user_7268601 0
Viewed 3885

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.

yargs typescript node.js
4 Answers

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

npm install --save @types/yargs

user_3361070

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.`);
    });
})();
user_30706130

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
user_124218710

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
user_24521960
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