PSFPortal/app/util/form.js
2019-12-30 09:27:49 -05:00

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// Thanks to https://lengstorf.com/get-form-values-as-json/
/**
* Checks that an element has a non-empty `name` and `value` property.
* @param {Element} element the element to check
* @return {Bool} true if the element is an input, false if not
*/
const isValidElement = element => {
return element.name && element.value;
};
/**
* Checks if an elements value can be saved (e.g. not an unselected checkbox).
* @param {Element} element the element to check
* @return {Boolean} true if the value should be added, false if not
*/
const isValidValue = element => {
return (!['checkbox', 'radio'].includes(element.type) || element.checked);
};
/**
* Checks if an input is a checkbox, because checkboxes allow multiple values.
* @param {Element} element the element to check
* @return {Boolean} true if the element is a checkbox, false if not
*/
const isCheckbox = element => element.type === 'checkbox';
/**
* Checks if an input is a `select` with the `multiple` attribute.
* @param {Element} element the element to check
* @return {Boolean} true if the element is a multiselect, false if not
*/
const isMultiSelect = element => element.options && element.multiple;
/**
* Retrieves the selected options from a multi-select as an array.
* @param {HTMLOptionsCollection} options the options for the select
* @return {Array} an array of selected option values
*/
const getSelectValues = options => [].reduce.call(options, (values, option) => {
return option.selected ? values.concat(option.value) : values;
}, []);
/**
* Retrieves input data from a form and returns it as a JSON object.
* @param {HTMLFormControlsCollection} elements the form elements
* @return {Object} form data as an object literal
*/
export const formToJSON = form => [].reduce.call(form.getElementsByTagName("*"), (data, element) => {
// Make sure the element has the required properties and should be added.
if (isValidElement(element) && isValidValue(element)) {
/*
* Some fields allow for more than one value, so we need to check if this
* is one of those fields and, if so, store the values as an array.
*/
if (isCheckbox(element)) {
data[element.name] = (data[element.name] || []).concat(element.value);
} else if (isMultiSelect(element)) {
data[element.name] = getSelectValues(element);
} else {
data[element.name] = element.value;
}
}
return data;
}, {});