title: How to get all the keys in a joi schema?
body: <p>I had a joi schema like this</p>
  
  <pre><code>const userModel = Joi.object({
    id: Joi.string().min(3).max(50),
    username: Joi.string().min(10).max(100)
    ... other 10 properties
  })
  </code></pre>
  
  <p>the thing is I wanted to get the values of all the keys like </p>
  
  <p><code>["id","username",...]</code></p>
  
  <p>I tried using Object.keys(userModel), but that is returning an unexpected value like</p>
  
  <pre><code>[
    "isJoi",
    "_currentJoi",
    "_type",
    "_settings",
    "_baseType",
    "_valids",
    "_invalids",
    "_tests",
    "_refs",
    "_flags",
    "_description",
    "_unit",
    "_notes",
    "_tags",
    "_examples",
    "_meta",
    "_inner"
  ]
  </code></pre>