.md Files Link Validation

That is my first Node.JS library. It is a simple command-line program which receives a .md file path as parameter and validate each link in the file, if it has any. If, instead of passing a file path, the user pass a directory path, it will validate each link of each .md file in the directory. The output is formatted by default as a list to allow for a better visualization in the command-line:

Default output:

Links validation results:

File name: file1.md Link placeholder: {link_placeholder} ⎆ Status: 200 - OK

Link placeholder: {link_placeholder} ⎆ Status: 404 - Not Found

Link placeholder: {link_placeholder} ⎆ Status: Error ⎆ Status: ENOTFOUND

File name: file2.md Link placeholder: {link_placeholder} ⎆ Status: 200 - OK

Link placeholder: {link_placeholder} ⎆ Status: 301 - Moved Permanently

...but it can also output in JSON format passing the "-j" or "--json" flag:

JSON output model:

[
  {
    "filename": "file1.md",
    "links": [
      {
        "id": 1,
        "placeholder": "<link_placeholder>",
        "url": "https://link1.com.br",
        "status": "200 - OK"
      },
      {
        "id": 2,
        "placeholder": "<link_placeholder>",
        "url": "https://link2.com",
        "status": "200 - OK"
      },
      {
        "id": 3,
        "placeholder": "<link_placeholder>",
        "url": "https://link2.com",
        "status": "404 - Not Found"
      }
    ]
  },
  {
    "filename": "file2.md",
    "links": [
      {
        "id": 1,
        "placeholder": "<link_placeholder>",
        "url": "https://link1.com.br",
        "status": "200 - OK"
      },
      {
        "id": 2,
        "placeholder": "<link_placeholder>",
        "url": "httpslink2.com",
        "status": "Error",
        "errorCode": "ERR_INVALID_URL"
      }
    ]
  }
]

If you have any suggestions of improvement, please contact me, I'll be really thankful! :)