Adding new Visual Selector for choosing the area of the webpage to monitor - playwright/browserless only (#566)

changedetectionio/static/js/limit.js

@@ -0,0 +1,56 @@
+/**
+ * debounce
+ * @param {integer} milliseconds This param indicates the number of milliseconds
+ *     to wait after the last call before calling the original function.
+ * @param {object} What "this" refers to in the returned function.
+ * @return {function} This returns a function that when called will wait the
+ *     indicated number of milliseconds after the last call before
+ *     calling the original function.
+ */
+Function.prototype.debounce = function (milliseconds, context) {
+    var baseFunction = this,
+        timer = null,
+        wait = milliseconds;
+
+    return function () {
+        var self = context || this,
+            args = arguments;
+
+        function complete() {
+            baseFunction.apply(self, args);
+            timer = null;
+        }
+
+        if (timer) {
+            clearTimeout(timer);
+        }
+
+        timer = setTimeout(complete, wait);
+    };
+};
+
+/**
+* throttle
+* @param {integer} milliseconds This param indicates the number of milliseconds
+*     to wait between calls before calling the original function.
+* @param {object} What "this" refers to in the returned function.
+* @return {function} This returns a function that when called will wait the
+*     indicated number of milliseconds between calls before
+*     calling the original function.
+*/
+Function.prototype.throttle = function (milliseconds, context) {
+    var baseFunction = this,
+        lastEventTimestamp = null,
+        limit = milliseconds;
+
+    return function () {
+        var self = context || this,
+            args = arguments,
+            now = Date.now();
+
+        if (!lastEventTimestamp || now - lastEventTimestamp >= limit) {
+            lastEventTimestamp = now;
+            baseFunction.apply(self, args);
+        }
+    };
+};