formToData.js

        function formToData(form) {
            const formData = new FormData(form.get()[0])
            var params = new Map()
            var errors = []
            var inputElements = {}

            // Initially iterate through all the inputs
            form.find(':input').each(function(key, value) {
                var elem = $(this)
                var name = elem.attr('name')
                if (name !== undefined) {
                    inputElements[name] = elem
                    var emptyValue = elem.data('empty')
                    if (emptyValue !== undefined) {
                        params[name] = emptyValue
                    }
                }
            })

            // Now iterate through all the supplied form values
            for (let [paramKey, paramValue] of formData.entries()) {
                let inputElement = inputElements[paramKey]
                let dataType = inputElement.data('type')
                try {
                    if (!inputElement[0].checkValidity()) {
                        // Invalid inputs return paramValue of '',
                        // so we need to differentiate between that
                        // and an actually empty input
                        throw Error()
                    } else if (dataType === 'integer') {
                        if (!paramValue) {
                            params[paramKey] = null
                        } else {
                            if (paramValue.includes('.')) {
                                throw Error()
                            }
                            paramValue = parseInt(paramValue)
                            if (paramValue != paramValue) {
                                throw Error()
                            }
                            params[paramKey] = paramValue
                        }
                    } else if (dataType === 'number') {
                        if (!paramValue) {
                            params[paramKey] = null
                        } else {
                            paramValue = parseFloat(paramValue)
                            if (paramValue != paramValue) {
                                throw Error()
                            }
                            params[paramKey] = paramValue
                        }
                    } else if (dataType === 'boolean') {
                        params[paramKey] = true
                    } else if (dataType === 'array') {
                        if (inputElement.is('select')) {
                            params[paramKey] = params[paramKey].concat([paramValue])
                        } else {
                            params[paramKey] = JSON.parse(paramValue)
                        }
                    } else if (dataType === 'object') {
                        params[paramKey] = JSON.parse(paramValue)
                    } else {
                        params[paramKey] = paramValue
                    }
                } catch(e) {
                    errors.push(paramKey)
                }
            }
            return params
        }

nice work