1 files changed, 33 insertions, 0 deletions
diff --git a/static/lib.js b/static/lib.js
index 3c11e23f..ab279353 100644
--- a/static/lib.js
+++ b/static/lib.js
@@ -3,6 +3,25 @@
   General procedures which in theory could be used anywhere.
  */
 
+HTMLElement.prototype._addEventListener = HTMLElement.prototype.addEventListener;
+HTMLElement.prototype.addEventListener = function (name, proc) {
+    if (! this.listeners) this.listeners = {};
+    if (! this.listeners[name]) this.listeners[name] = [];
+    this.listeners[name].push(proc);
+    return this._addEventListener(name, proc);
+};
+
+
+
+/* list of lists -> list of tuples */
+function zip(...args) {
+    // console.log(args);
+    if (args === []) return [];
+    return [...Array(Math.min(...args.map(x => x.length))).keys()]
+        .map((_, i) => args.map(lst => lst[i]));
+}
+
+
 /* ----- Date Extensions ---------------------------- */
 
 /*
@@ -131,4 +150,18 @@ function format_date(date, str) {
 Object.prototype.format = function () { return this; } /* any number of arguments */
 Date.prototype.format = function (str) { return format_date (this, str); }
 
+/*
+ * Finds the first element of the DOMTokenList whichs value matches
+ * the supplied regexp. Returns a pair of the index and the value.
+ */
+DOMTokenList.prototype.find = function (regexp) {
+    let entries = this.entries();
+    let entry;
+    while (! (entry = entries.next()).done) {
+        if (entry.value[1].match(regexp)) {
+            return entry.value;
+        }
+    }
+}
+
 const xcal = "urn:ietf:params:xml:ns:icalendar-2.0";