DEV Community

Discussion on: How to easily convert HTML Form to JSON

View post

Replies for: Right. Do you have examples of inputs with the same name? I can only think of radio inputs, but in that case, it will only take the one that was se...

 
jordanfinners profile image
Jordan Finneran •

It probably not that common but if you want a list of things a user could check.

For example, if there was a list of languages as checkbox inputs, they could check each one they knew and the output of the Full Example would give you an Array of the languages the user knows.
If you open the Interactive Example in JSFiddle you can see the console output for this :)

Thread Thread
 
ndrean profile image
NDREAN •

I have a question; does this make sense if you use name="lang[js]" and name="lang[py]" ?

Thread Thread
 
jordanfinners profile image
Jordan Finneran •

You could also do this. It depends what processing you want to do afterwards. :)
I've included both in here jsfiddle.net/8fL3vra1/
Where you can run it, what you get is:

{
  lang[js]: "on",
  lang[py]: "on",
  languages: ["javascript", "python"]
}
Enter fullscreen mode Exit fullscreen mode

My personal preference is to get the list of items but it's completely up to you how you want to achieve it :D

Thread Thread
 
austingil profile image
Austin Gil •

Oh yeah, that would make sense. I usually give each checkbox its own name, and if they are related, I put them inside a <fieldset>. I'll need to remember this if I'm working with objects and want a list.

Usually I just wrap the data in a URLSearchParams and send it to the backend like that. URLSearchParams will handle the list if there are multiple entries with the same name.

document.querySelector('form').addEventListener('submit', (e) => {
  const formData = new FormData(e.target)
  const params = new URLSearchParams(formData)

  fetch(`https://example.com?${params.toString()}`)

  fetch(`https://example.com`, {
    method: 'POST',
    body: params
  })

  e.preventDefault()
})
Enter fullscreen mode Exit fullscreen mode
Thread Thread
 
ndrean profile image
NDREAN • • Edited

If you POST, I believe you can do directly body: new FormData(e.target)
if you GET and adjoin a query string, you may indeed need URLSearchParams

Thread Thread
 
austingil profile image
Austin Gil •

Ah yes. This is true. My only issue with this is using FormData in the request body changes the request headers from the default application/x-www-form-urlencoded to multipart/form-data. This has caused me issues before, so I try to avoid it.