Add node modules and new code for release (#57)

Co-authored-by: taakleton <taakleton@users.noreply.github.com>

node_modules/underscore/modules/throttle.js

@@ -0,0 +1,47 @@
+import now from './now.js';
+
+// Returns a function, that, when invoked, will only be triggered at most once
+// during a given window of time. Normally, the throttled function will run
+// as much as it can, without ever going more than once per `wait` duration;
+// but if you'd like to disable the execution on the leading edge, pass
+// `{leading: false}`. To disable execution on the trailing edge, ditto.
+export default function throttle(func, wait, options) {
+  var timeout, context, args, result;
+  var previous = 0;
+  if (!options) options = {};
+
+  var later = function() {
+    previous = options.leading === false ? 0 : now();
+    timeout = null;
+    result = func.apply(context, args);
+    if (!timeout) context = args = null;
+  };
+
+  var throttled = function() {
+    var _now = now();
+    if (!previous && options.leading === false) previous = _now;
+    var remaining = wait - (_now - previous);
+    context = this;
+    args = arguments;
+    if (remaining <= 0 || remaining > wait) {
+      if (timeout) {
+        clearTimeout(timeout);
+        timeout = null;
+      }
+      previous = _now;
+      result = func.apply(context, args);
+      if (!timeout) context = args = null;
+    } else if (!timeout && options.trailing !== false) {
+      timeout = setTimeout(later, remaining);
+    }
+    return result;
+  };
+
+  throttled.cancel = function() {
+    clearTimeout(timeout);
+    previous = 0;
+    timeout = context = args = null;
+  };
+
+  return throttled;
+}