add support for callback functions in config (#1)

Author: Éric

django_ckeditor_5/static/django_ckeditor_5/app.js

@@ -26,10 +26,10 @@ function getCookie(name) {
 /**
  * Checks whether the element or its children match the query and returns
  * an array with the matches.
- * 
+ *
  * @param {!HTMLElement} element
  * @param {!string} query
- * 
+ *
  * @returns {array.<HTMLElement>}
  */
 function resolveElementArray(element, query) {
@@ -39,9 +39,9 @@ function resolveElementArray(element, query) {
 /**
  * This function initializes the CKEditor inputs within an optional element and
  * assigns properties necessary for the correct operation
- * 
+ *
  * @param {HTMLElement} [element=document.body] - The element to search for elements
- * 
+ *
  * @returns {void}
  */
 function createEditors(element = document.body) {
@@ -81,6 +81,12 @@ function createEditors(element = document.body) {
                    var regex = new RegExp(match[1], match[2]);
                    return regex;
                 }
+                if (value.toString().startsWith('::function::-')) {
+                   var funName = value.toString().split('-')[1]
+                   // callback must be installed into this global object first
+                   var func = window.djangoCKEditor5Functions[funcName]
+                   return func;
+                }
                 return value;
             }
         );
@@ -126,10 +132,10 @@ function createEditors(element = document.body) {
  * This function filters the list of mutations only by added elements, thus
  * eliminates the occurrence of text nodes and tags where it does not make sense
  * to try to use with `QuerySelectorAll()` and `matches()` functions.
- * 
+ *
  * @param {MutationRecord} recordList - It is the object inside the array
  * passed to the callback of a MutationObserver.
- * 
+ *
  * @returns {Array} Array containing filtered nodes.
  */
 function getAddedNodes(recordList) {