From 2c04f6f67013afd94d93efb48423e972a25c4df6 Mon Sep 17 00:00:00 2001
From: Felix Hamann <felix.hamann@campus.lmu.de>
Date: Sun, 7 Apr 2019 13:48:58 +0200
Subject: [PATCH] refactor reactive submit button JS utility

---
 src/Foundation.hs       |   2 +-
 static/js/utils/form.js | 151 ++++++++++++++++++++++++++++------------
 2 files changed, 109 insertions(+), 44 deletions(-)

diff --git a/src/Foundation.hs b/src/Foundation.hs
index 047a69955..3692aa39c 100644
--- a/src/Foundation.hs
+++ b/src/Foundation.hs
@@ -1075,8 +1075,8 @@ siteLayout' headingOverride widget = do
       -- addScript $ StaticR js_utils_asyncTableFilter_js
       -- addScript $ StaticR js_utils_checkAll_js
       -- addScript $ StaticR js_utils_httpClient_js
-      -- addScript $ StaticR js_utils_form_js
       -- JavaScript utils
+      addScript $ StaticR js_utils_form_js
       addScript $ StaticR js_utils_inputs_js
       addScript $ StaticR js_utils_modal_js
       addScript $ StaticR js_utils_poc_js
diff --git a/static/js/utils/form.js b/static/js/utils/form.js
index 77437a3e1..ffb6e5f5c 100644
--- a/static/js/utils/form.js
+++ b/static/js/utils/form.js
@@ -3,25 +3,15 @@
 
   window.utils = window.utils || {};
 
+  var formUtilities = [];
+
   var JS_INITIALIZED = 'js-form-initialized';
-  var SUBMIT_BUTTON_SELECTOR = '[type="submit"]:not([formnovalidate])';
   var AUTOSUBMIT_BUTTON_SELECTOR = '[type="submit"][data-autosubmit]';
   var AJAX_SUBMIT_FLAG = 'ajaxSubmit';
 
   var FORM_GROUP_CLASS = 'form-group';
   var FORM_GROUP_WITH_ERRORS_CLASS = 'form-group--has-error';
 
-  function formValidator(inputs) {
-    var done = true;
-    inputs.forEach(function(inp) {
-      var len = inp.value.trim().length;
-      if (done && len === 0) {
-        done = false;
-      }
-    });
-    return done;
-  }
-
   window.utils.form = function(form, options) {
     options = options || {};
 
@@ -77,50 +67,119 @@
     };
   };
 
-  // registers input-listener for each element in <inputs> (array) and
-  // enables <button> if <formValidator> for these inputs returns true
-  window.utils.reactiveButton = function(form, options) {
-    var button = form.querySelector(SUBMIT_BUTTON_SELECTOR);
-    var requireds = Array.from(form.querySelectorAll('[required]'));
+  /**
+   *
+   * Reactive Submit Button Utility
+   *  disables a forms LAST sumit button as long as the required inputs are invalid
+   *  (only checks if the value of the inputs are not empty)
+   *
+   * Attribute: uw-reactive-submit-button
+   *  works only on `form` elements
+   *
+   * Params:
+   *  data-formnorequired: string
+   *    If present the submit button will never get disabled
+   *
+   * Example usage:
+   *  <form uw-reactive-submit-button>
+   *   <input type="text" required>
+   *   <button type="submit">
+   *  </form>
+   */
 
-    if (!button || button.matches(AUTOSUBMIT_BUTTON_SELECTOR)) {
-      return false;
+  var REACTIVE_SUBMIT_BUTTON_UTIL_NAME = 'reactiveSubmitButton';
+  var REACTIVE_SUBMIT_BUTTON_UTIL_SELECTOR = 'form';
+
+  var REACTIVE_SUBMIT_BUTTON_INITIALIZED_CLASS = 'reactive-submit-button--initialized';
+
+  var reactiveButtonUtil = function(element) {
+    var requiredInputs;
+    var submitButton;
+
+    function init() {
+      if (!element) {
+        throw new Error('Reactive Submit Button utility cannot be setup without an element!');
+      }
+
+      if (element.classList.contains(REACTIVE_SUBMIT_BUTTON_INITIALIZED_CLASS)) {
+        throw new Error('Reactive Submit Button utility already initialized!');
+      }
+
+      // abort if form has param data-formnorequired
+      if (element.dataset.formnorequired !== undefined) {
+        throw new Error('Form has formnorequired data attribute. Will skip setup of reactive submit button.');
+      }
+
+      requiredInputs = Array.from(element.querySelectorAll('[required]'));
+      if (!requiredInputs) {
+        // abort if form has no required inputs
+        throw new Error('Submit button has formnorequired data attribute. Will skip setup of reactive submit button.');
+      }
+
+      var submitButtons = Array.from(element.querySelectorAll('[type="submit"]'));
+      if (!submitButtons) {
+        throw new Error('Reactive Submit Button utility couldn\'t find any submit buttons!');
+      }
+      submitButton = submitButtons.reverse()[0];
+      // abort if form has param data-formnorequired
+      if (submitButton.dataset.formnorequired !== undefined) {
+        return false;
+      }
+
+      setupInputs();
+      updateButtonState();
+
+      element.classList.add(REACTIVE_SUBMIT_BUTTON_INITIALIZED_CLASS);
+
+      return {
+        name: REACTIVE_SUBMIT_BUTTON_UTIL_NAME,
+        element: element,
+        destroy: function() {},
+      };
     }
 
-    if (requireds.length == 0) {
-      return false;
-    }
-
-    if (typeof button.dataset.formnorequired !== 'undefined' && button.dataset.formnorequired !== null) {
-      button.addEventListener('click', function() {
-        form.submit();
+    function setupInputs() {
+      requiredInputs.forEach(function(el) {
+        var checkbox = el.getAttribute('type') === 'checkbox';
+        var eventType = checkbox ? 'change' : 'input';
+        el.addEventListener(eventType, function() {
+          updateButtonState();
+        });
       });
-      return false;
     }
-    updateButtonState();
-
-    requireds.forEach(function(el) {
-      var checkbox = el.getAttribute('type') === 'checkbox';
-      var eventType = checkbox ? 'change' : 'input';
-      el.addEventListener(eventType, function() {
-        updateButtonState();
-      });
-    });
 
     function updateButtonState() {
-      if (formValidator(requireds) === true) {
-        button.removeAttribute('disabled');
+      if (inputsValid()) {
+        submitButton.removeAttribute('disabled');
       } else {
-        button.setAttribute('disabled', 'true');
+        console.log('setting disabled', { submitButton });
+        submitButton.setAttribute('disabled', 'true');
       }
     }
 
-    return {
-      scope: form,
-      destroy: function() {},
-    };
+    function inputsValid() {
+      var done = true;
+      requiredInputs.forEach(function(inp) {
+        var len = inp.value.trim().length;
+        if (done && len === 0) {
+          done = false;
+        }
+      });
+      return done;
+    }
+
+    return init();
   };
 
+  formUtilities.push({
+    name: REACTIVE_SUBMIT_BUTTON_UTIL_NAME,
+    selector: REACTIVE_SUBMIT_BUTTON_UTIL_SELECTOR,
+    setup: reactiveButtonUtil,
+  });
+
+
+
+
   window.utils.interactiveFieldset = function(form, options) {
     options = options || {};
     var fieldSets = options.fieldSets;
@@ -199,4 +258,10 @@
       },
     };
   };
+
+  // register the collected form utilities
+  if (UtilRegistry) {
+    formUtilities.forEach(UtilRegistry.register);
+  }
+
 })();