get data from form element

customFormData.js

export const isValidElement = element => {
    return element.name && (element.value || element.value === '')
}
export const isValidValue = element => {
    return (!['checkbox', 'radio'].includes(element.type) || element.checked)
}
export const isCheckbox = element => element.type === 'checkbox'

export const isRadioButton = element => element.type === 'radio'

export const isMultiSelect = element => element.options && element.multiple

export const isSameName = element => !isCheckbox(element) && !isMultiSelect(element) && !isRadioButton(element) && element.form.elements[element.name].length

export const getSelectValues = options => [].reduce.call(options, (values, option) => {
    return option.selected ? values.concat(option.value) : values
}, [])

export const dataToObject = elements => [].reduce.call(elements, (data, element) => {

    if (isValidElement(element) && isValidValue(element)) {

        if (isCheckbox(element)) {
            data[element.name] = (data[element.name] || []).concat(element.value)
        } else if (isMultiSelect(element)) {
            data[element.name] = getSelectValues(element)
        }
        else if (isSameName(element)) {
            data[element.name] = (data[element.name] || []).concat(element.value)
        }
        else {
            data[element.name] = element.value
        }
    }

    return data
}, {})


/*example
import * as CustomFormData from './customFormData.js'

document.querySelector('#super-form').addEventListener('submit', (e) => {
    e.preventDefault()
    const data = CustomFormData.formToJSON(e.target.elements)
    axios({
        method: 'put',
        headers: {'X-Requested-With': 'XMLHttpRequest'},
        url: e.target.action,
        params: data
    })
})
*/