如何在提交侦听器上传递表单数据，以便 axios 可以发布表单数据？

Question

I have a form like the following.

<form class="comment-post" method="POST" action="/api/v1/comment/<%= post._id %>" enctype="multipart/form-data>
   <div class="comment-section">
         <textarea rows="4" name="comment"></textarea>
         <button type="submit" class="button">Submit</button>
  </div>
</form>

There can be more than one form with class 'comment -post'. I would like to add event listener on form submit so that the request is ajax like, as in the following.

const commentPostForms = document.querySelectorAll('.comment-post')

commentPostForms.forEach(form => {
    form.addEventListener('submit', function(e) {
        e.preventDefault()

        axios
            .post(this.action)
            .then(res=>{
                console.log(res)
            })
            .catch(console.error);

    })
})

My question is how do I submit the form data along with my axios request. Currently, no form data is being sent.

I tried the following (edited),

function(e) {
    e.preventDefault()
    const formData = new FormData(e.target)

     axios
        .post(e.target.action, formData)
         .then(res=>{
              console.log(res)
          })
         .catch(console.error);

 })

On the node js express server side I am doing console of the received object to see if the data has been actually passed.

router.post('/comment/:post_id/', comment );

const comment = (req, res) => {
    console.log(req.body)
    res.json(req.body);
}

I do not see 'comment' on req.body console.log

Answer 1

You need to generate the form data using the target of the event. So you should do:

const commentPostForms = document.querySelectorAll('.comment-post')

commentPostForms.forEach(form => {
    form.addEventListener('submit', (e) => {
        e.preventDefault()
        const formData = new FormData(e.target);

        axios
            .post(e.target.action, formData)
            .then(res=>{
                console.log(res)
            })
            .catch(console.error);

    })
})

Also, in your html set the enctype to form data. So you will have:

<form class="comment-post" enctype="multipart/formdata" action="/api/v1/comment/<%= post._id %>">
   <div class="comment-section">
       <textarea rows="4" name="comment"></textarea>
       <button type="submit" class="button">Submit</button>
  </div>
</form>

If you want to check if they key/pair your form data is really there. You can do after generating the form data:

for (let pair of formData.entries()) {
   console.log(pair[0]+ ', ' + pair[1]); 
}