npm init -y

https://www.npmjs.com/package/yargs

npm i yargs@13.2.1 --save
```
node main.js --num 10
---------------
Executando o script a partir do diretório C:\primeiro-projeto
O fatorial de 6 é 720
O fatorial3 de 4 é 24
O fatorial2 de 5 é 120
O fatorial de 10 é 3628800
Arquivo test.txt salvo com sucesso.
script prestes a ser finalizado !
```
node main.js -n 10
---------------
Executando o script a partir do diretório C:\primeiro-projeto
O fatorial de 6 é 720
O fatorial3 de 4 é 24
O fatorial2 de 5 é 120
O fatorial de 10 é 3628800
Arquivo test.txt salvo com sucesso.
script prestes a ser finalizado !
```

npm i typescript -g
---------------
C:\Users\Felipe\AppData\Roaming\npm\tsserver -> C:\Users\Felipe\AppData\Roaming\npm\node_modules\typescript\bin\tsserver
C:\Users\Felipe\AppData\Roaming\npm\tsc -> C:\Users\Felipe\AppData\Roaming\npm\node_modules\typescript\bin\tsc
+ typescript@3.3.3
updated 1 package in 4.885s


tsc --init
---------------
message TS6071: Successfully created a tsconfig.json file.


tsc
---------------
main.ts:2:58 - error TS2580: Cannot find name 'process'. Do you need to install type definitions for node? Try `npm i @types/node` and then add `node` to the types field in your tsconfig.

2 console.log(`Executando o script a partir do diretório ${process.cwd()}`)
                                                           ~~~~~~~

main.ts:5:12 - error TS2580: Cannot find name 'require'. Do you need to install type definitions for node? Try `npm i @types/node` and then add `node` to the types field in your tsconfig.

5 const fs = require('fs')
             ~~~~~~~

main.ts:12:18 - error TS2580: Cannot find name 'require'. Do you need to install type definitions for node? Try `npm i @types/node` and then add `node` to the types field in your tsconfig.

12 const fatorial = require('./fatorial')      // primeiro na ordem de precedência (módulo com package.json)
                    ~~~~~~~

main.ts:13:19 - error TS2580: Cannot find name 'require'. Do you need to install type definitions for node? Try `npm i @types/node` and then add `node` to the types field in your tsconfig.

13 const fatorial3 = require('./fatorial3')    // segundo
                     ~~~~~~~

main.ts:14:19 - error TS2580: Cannot find name 'require'. Do you need to install type definitions for node? Try `npm i @types/node` and then add `node` to the types field in your tsconfig.

14 const fatorial2 = require('./fatorial2')    // terceiro e último
                     ~~~~~~~

main.ts:22:14 - error TS2580: Cannot find name 'require'. Do you need to install type definitions for node? Try `npm i @types/node` and then add `node` to the types field in your tsconfig.

22 const argv = require('yargs')
                ~~~~~~~

main.ts:31:13 - error TS2580: Cannot find name 'module'. Do you need to install type definitions for node? Try `npm i @types/node` and then add `node` to the types field in your tsconfig.

31 console.log(module.paths) // [ 'C:\\primeiro-projeto\\node_modules', 'C:\\node_modules' ]
               ~~~~~~

main.ts:34:1 - error TS2580: Cannot find name 'process'. Do you need to install type definitions for node? Try `npm i @types/node` and then add `node` to the types field in your tsconfig.

34 process.on('exit', () => {
   ~~~~~~~


Found 8 errors.




npm i @types/node --save-dev
---------------
npm WARN primeiro-projeto@1.0.0 No repository field.

+ @types/node@11.9.4
added 1 package from 35 contributors and audited 68 packages in 3.005s
found 0 vulnerabilities




npm i @types/yargs -D
---------------
npm WARN primeiro-projeto@1.0.0 No repository field.

+ @types/yargs@12.0.9
added 1 package from 6 contributors and audited 69 packages in 2.051s
found 0 vulnerabilities


tsc -w
---------------
[23:15:38] Starting compilation in watch mode...

[23:15:41] Found 0 errors. Watching for file changes.


node ./dist/main.js --num 10
---------------
Executando o script a partir do diretório C:\primeiro-projeto
O fatorial de 6 é 720
O fatorial de 10 é 3628800
[ 'C:\\primeiro-projeto\\dist\\node_modules',
  'C:\\primeiro-projeto\\node_modules',
  'C:\\node_modules' ]
Arquivo test.txt salvo com sucesso.
script prestes a ser finalizado !