file upload ajax

controller.rb

bucket = Aws::S3::Bucket.new(name: 'truck-parts')
@signed_upload_url = bucket.presigned_post(
  key: 'public/${filename}', 
  success_action_status: '201', 
  acl: 'public-read',
  signature_expiration: 1.minute.from_now
)

file-upload-ajax.js

$(function() {
    $('input:file').change(function() {
        let form = $('form')
        let url = form.data('url')    
        
        $.each(this.files, function(index, file) {            
            let formData = new FormData()
            $.each(form.data('fields'), function(key, value) {
                formData.append(key, value)
            })
            formData.append('file', file)

            $.ajax({
                method: 'post',
                url: url,

                data: formData,

                cache: false,
                contentType: false,
                processData: false
            })
        })
    })
})