https://lums.edu.pk/core/misc/form.js?v=10.2.12

1/**
2 * @file
3 * Form features.
4 */
5
6/**
7 * Triggers when a value in the form changed.
8 *
9 * The event triggers when content is typed or pasted in a text field, before
10 * the change event triggers.
11 *
12 * @event formUpdated
13 */
14
15/**
16 * Triggers when a click on a page fragment link or hash change is detected.
17 *
18 * The event triggers when the fragment in the URL changes (a hash change) and
19 * when a link containing a fragment identifier is clicked. In case the hash
20 * changes due to a click this event will only be triggered once.
21 *
22 * @event formFragmentLinkClickOrHashChange
23 */
24
25(function ($, Drupal, debounce) {
26  /**
27   * Retrieves the summary for the first element.
28   *
29   * @return {string}
30   *   The text of the summary.
31   */
32  $.fn.drupalGetSummary = function () {
33    const callback = this.data('summaryCallback');
34
35    if (!this[0] || !callback) {
36      return '';
37    }
38
39    const result = callback(this[0]);
40
41    return result ? result.trim() : '';
42  };
43
44  /**
45   * Sets the summary for all matched elements.
46   *
47   * @param {function} callback
48   *   Either a function that will be called each time the summary is
49   *   retrieved or a string (which is returned each time).
50   *
51   * @return {jQuery}
52   *   jQuery collection of the current element.
53   *
54   * @fires event:summaryUpdated
55   *
56   * @listens event:formUpdated
57   */
58  $.fn.drupalSetSummary = function (callback) {
59    const self = this;
60
61    // To facilitate things, the callback should always be a function. If it's
62    // not, we wrap it into an anonymous function which just returns the value.
63    if (typeof callback !== 'function') {
64      const val = callback;
65      callback = function () {
66        return val;
67      };
68    }
69
70    return (
71      this.data('summaryCallback', callback)
72        // To prevent duplicate events, the handlers are first removed and then
73        // (re-)added.
74        .off('formUpdated.summary')
75        .on('formUpdated.summary', () => {
76          self.trigger('summaryUpdated');
77        })
78        // The actual summaryUpdated handler doesn't fire when the callback is
79        // changed, so we have to do this manually.
80        .trigger('summaryUpdated')
81    );
82  };
83
84  /**
85   * Prevents consecutive form submissions of identical form values.
86   *
87   * Repetitive form submissions that would submit the identical form values
88   * are prevented, unless the form values are different to the previously
89   * submitted values.
90   *
91   * This is a simplified re-implementation of a user-agent behavior that
92   * should be natively supported by major web browsers, but at this time, only
93   * Firefox has a built-in protection.
94   *
95   * A form value-based approach ensures that the constraint is triggered for
96   * consecutive, identical form submissions only. Compared to that, a form
97   * button-based approach would (1) rely on [visible] buttons to exist where
98   * technically not required and (2) require more complex state management if
99   * there are multiple buttons in a form.
100   *
101   * This implementation is based on form-level submit events only and relies
102   * on jQuery's serialize() method to determine submitted form values. As such,
103   * the following limitations exist:
104   *
105   * - Event handlers on form buttons that preventDefault() do not receive a
106   *   double-submit protection. That is deemed to be fine, since such button
107   *   events typically trigger reversible client-side or server-side
108   *   operations that are local to the context of a form only.
109   * - Changed values in advanced form controls, such as file inputs, are not
110   *   part of the form values being compared between consecutive form submits
111   *   (due to limitations of jQuery.serialize()). That is deemed to be
112   *   acceptable, because if the user forgot to attach a file, then the size of
113   *   HTTP payload will most likely be small enough to be fully passed to the
114   *   server endpoint within seconds, or even milliseconds. If a user
115   *   mistakenly attached a wrong file and is technically versed enough to
116   *   cancel the form submission (and HTTP payload) in order to attach a
117   *   different file, then that edge-case is not supported here.
118   *
119   * Lastly, all forms submitted via HTTP GET are idempotent by definition of
120   * HTTP standards, so excluded in this implementation.
121   *
122   * @type {Drupal~behavior}
123   */
124  Drupal.behaviors.formSingleSubmit = {
125    attach() {
126      function onFormSubmit(e) {
127        const $form = $(e.currentTarget);
128        const formValues = $form.serialize();
129        const previousValues = $form.attr('data-drupal-form-submit-last');
130        if (previousValues === formValues) {
131          e.preventDefault();
132        } else {
133          $form.attr('data-drupal-form-submit-last', formValues);
134        }
135      }
136
137      $(once('form-single-submit', 'body')).on(
138        'submit.singleSubmit',
139        'form:not([method~="GET"])',
140        onFormSubmit,
141      );
142    },
143  };
144
145  /**
146   * Sends a 'formUpdated' event each time a form element is modified.
147   *
148   * @param {HTMLElement} element
149   *   The element to trigger a form updated event on.
150   *
151   * @fires event:formUpdated
152   */
153  function triggerFormUpdated(element) {
154    $(element).trigger('formUpdated');
155  }
156
157  /**
158   * Collects the IDs of all form fields in the given form.
159   *
160   * @param {HTMLFormElement} form
161   *   The form element to search.
162   *
163   * @return {Array}
164   *   Array of IDs for form fields.
165   */
166  function fieldsList(form) {
167    // We use id to avoid name duplicates on radio fields and filter out
168    // elements with a name but no id.
169    return [].map.call(form.querySelectorAll('[name][id]'), (el) => el.id);
170  }
171
172  /**
173   * Triggers the 'formUpdated' event on form elements when they are modified.
174   *
175   * @type {Drupal~behavior}
176   *
177   * @prop {Drupal~behaviorAttach} attach
178   *   Attaches formUpdated behaviors.
179   * @prop {Drupal~behaviorDetach} detach
180   *   Detaches formUpdated behaviors.
181   *
182   * @fires event:formUpdated
183   */
184  Drupal.behaviors.formUpdated = {
185    attach(context) {
186      const $context = $(context);
187      const contextIsForm = context.tagName === 'FORM';
188      const $forms = $(
189        once('form-updated', contextIsForm ? $context : $context.find('form')),
190      );
191      let formFields;
192
193      if ($forms.length) {
194        // Initialize form behaviors, use $.makeArray to be able to use native
195        // forEach array method and have the callback parameters in the right
196        // order.

197        $.makeArray($forms).forEach((form) => {
198          const events = 'change.formUpdated input.formUpdated ';
199          const eventHandler = debounce((event) => {
200            triggerFormUpdated(event.target);
201          }, 300);
202          formFields = fieldsList(form).join(',');
203
204          form.setAttribute('data-drupal-form-fields', formFields);
205          $(form).on(events, eventHandler);
206        });
207      }
208      // On ajax requests context is the form element.
209      if (contextIsForm) {
210        formFields = fieldsList(context).join(',');
211        // @todo replace with form.getAttribute() when #1979468 is in.
212        const currentFields = $(context).attr('data-drupal-form-fields');
213        // If there has been a change in the fields or their order, trigger
214        // formUpdated.
215        if (formFields !== currentFields) {
216          triggerFormUpdated(context);
217        }
218      }
219    },
220    detach(context, settings, trigger) {
221      const $context = $(context);
222      const contextIsForm = context.tagName === 'FORM';
223      if (trigger === 'unload') {
224        once
225          .remove(
226            'form-updated',
227            contextIsForm ? $context : $context.find('form'),
228          )
229          .forEach((form) => {
230            form.removeAttribute('data-drupal-form-fields');
231            $(form).off('.formUpdated');
232          });
233      }
234    },
235  };
236
237  /**
238   * Prepopulate form fields with information from the visitor browser.
239   *
240   * @type {Drupal~behavior}
241   *
242   * @prop {Drupal~behaviorAttach} attach
243   *   Attaches the behavior for filling user info from browser.
244   */
245  Drupal.behaviors.fillUserInfoFromBrowser = {
246    attach(context, settings) {
247      const userInfo = ['name', 'mail', 'homepage'];
248      const $forms = $(
249        once('user-info-from-browser', '[data-user-info-from-browser]'),
250      );
251      if ($forms.length) {
252        userInfo.forEach((info) => {
253          const $element = $forms.find(`[name=${info}]`);
254          const browserData = localStorage.getItem(`Drupal.visitor.${info}`);
255          if (!$element.length) {
256            return;
257          }
258          const emptyValue = $element[0].value === '';
259          const defaultValue =
260            $element.attr('data-drupal-default-value') === $element[0].value;
261          if (browserData && (emptyValue || defaultValue)) {
262            $element.each(function (index, item) {
263              item.value = browserData;
264            });
265          }
266        });
267      }
268      $forms.on('submit', () => {
269        userInfo.forEach((info) => {
270          const $element = $forms.find(`[name=${info}]`);
271          if ($element.length) {
272            localStorage.setItem(`Drupal.visitor.${info}`, $element[0].value);
273          }
274        });
275      });
276    },
277  };
278
279  /**
280   * Sends a fragment interaction event on a hash change or fragment link click.
281   *
282   * @param {jQuery.Event} e
283   *   The event triggered.
284   *
285   * @fires event:formFragmentLinkClickOrHashChange
286   */
287  const handleFragmentLinkClickOrHashChange = (e) => {
288    let url;
289    if (e.type === 'click') {
290      url = e.currentTarget.location
291        ? e.currentTarget.location
292        : e.currentTarget;
293    } else {
294      url = window.location;
295    }
296    const hash = url.hash.substring(1);
297    if (hash) {
298      const $target = $(`#${hash}`);
299      $('body').trigger('formFragmentLinkClickOrHashChange', [$target]);
300
301      /**
302       * Clicking a fragment link or a hash change should focus the target
303       * element, but event timing issues in multiple browsers require a timeout.
304       */
305      setTimeout(() => $target.trigger('focus'), 300);
306    }
307  };
308
309  const debouncedHandleFragmentLinkClickOrHashChange = debounce(
310    handleFragmentLinkClickOrHashChange,
311    300,
312    true,
313  );
314
315  // Binds a listener to handle URL fragment changes.
316  $(window).on(
317    'hashchange.form-fragment',
318    debouncedHandleFragmentLinkClickOrHashChange,
319  );
320
321  /**
322   * Binds a listener to handle clicks on fragment links and absolute URL links
323   * containing a fragment, this is needed next to the hash change listener
324   * because clicking such links doesn't trigger a hash change when the fragment
325   * is already in the URL.
326   */
327  $(document).on(
328    'click.form-fragment',
329    'a[href*="#"]',
330    debouncedHandleFragmentLinkClickOrHashChange,
331  );
332})(jQuery, Drupal, Drupal.debounce);