1 files changed, 14 insertions, 0 deletions
diff --git a/src/shared/observe-dom.ts b/src/shared/observe-dom.ts
index e82ce1e..90a52ff 100644
--- a/src/shared/observe-dom.ts
+++ b/src/shared/observe-dom.ts
@@ -3,6 +3,12 @@ type ObserveDOMCallback = () => boolean;
 let callbacks: (ObserveDOMCallback | null)[] = [];
 let callbacksCalledCount = 0;
 
+/**
+ * Starts a MutationObserver on the document that invokes each
+ * registered callback.  A callback should return `true` when it
+ * has completed its work; once all callbacks are done the observer
+ * disconnects.
+ */
 const observer = new MutationObserver(() => {
 	for (let i = 0; i < callbacks.length; i++) {
 		const callback = callbacks[i];
@@ -24,6 +30,14 @@ observer.observe(document, {
 	subtree: true
 });
 
+/**
+ * Registers a callback to run on DOM mutations.
+ * The callback is invoked on each mutation tick and should return `true`
+ * when its work is finished.  When all callbacks have completed the
+ * observer stops.
+ *
+ * @param callback - Function that returns `true` when done.
+ */
 export function observeDOM(callback: ObserveDOMCallback) {
 	callbacks.push(callback);
 };