So I'm having this little generator, the info that get displayed should correspond to what values are populated on the database, the example below is a physical address

```
this.setState({
   companyEmail: json.data.companyEmail,
   company: json.data.company,
   line1: json.data.line1,
   line2: json.data.line2,
   city: json.data.city,
   ... 
});

```

So I could initialize those values with `null`, `undefined` or `""` it does not matter, on the fetch request the typeof those empty values turn to undefined.

Firebase don't like that, for me it cause no issue, I could hide the element by checking if it's true or false like so

```
{line1 && <span>{line1}<br /></span>}
{line2 && <span>{line2}<br /></span>}

```

Well I mean it works until I tried updating the database, I got this error

> 
> Error: Reference.set failed: First argument contains undefined in
>  property 'master.business.info.line2'
> 
> 
> 

What I want to do is kindof turning undefined to null, because when sending null remove the child from the db, it's treated like a real value.

On the server side, it's regular db update

```
master.update({
   company: company,
   line1: line1,
   line2: line2,
   city: city,
   ... 
})
.then(() => {
   response.sendStatus(200);
}).catch(function (err) {
   console.log(err);
   response.sendStatus(204);
});

```

I could use if statement and setState accordingly but that's too much work. I need to make to fetch request because I need those values, it's a form to edit info.

Also using empty strings like `""` is not good, it gets display inside span, paragraph or whatever.

This is not a duplicate, on react.js my goal is to not setState for undefined values and keep the init values on the constructor.