diff --git a/lib/web/eventsource/eventsource-stream.js b/lib/web/eventsource/eventsource-stream.js
index 754934568d0..59cf7468800 100644
--- a/lib/web/eventsource/eventsource-stream.js
+++ b/lib/web/eventsource/eventsource-stream.js
@@ -35,16 +35,16 @@ const SPACE = 0x20
 /**
  * @typedef eventSourceSettings
  * @type {object}
- * @property {string} lastEventId The last event ID received from the server.
- * @property {string} origin The origin of the event source.
- * @property {number} reconnectionTime The reconnection time, in milliseconds.
+ * @property {string} [lastEventId] The last event ID received from the server.
+ * @property {string} [origin] The origin of the event source.
+ * @property {number} [reconnectionTime] The reconnection time, in milliseconds.
  */
 
 class EventSourceStream extends Transform {
   /**
    * @type {eventSourceSettings}
    */
-  state = null
+  state
 
   /**
    * Leading byte-order-mark check.
@@ -63,7 +63,7 @@ class EventSourceStream extends Transform {
   eventEndCheck = false
 
   /**
-   * @type {Buffer}
+   * @type {Buffer|null}
    */
   buffer = null
 
@@ -78,8 +78,9 @@ class EventSourceStream extends Transform {
 
   /**
    * @param {object} options
-   * @param {eventSourceSettings} options.eventSourceSettings
-   * @param {Function} [options.push]
+   * @param {boolean} [options.readableObjectMode]
+   * @param {eventSourceSettings} [options.eventSourceSettings]
+   * @param {(chunk: any, encoding?: BufferEncoding | undefined) => boolean} [options.push]
    */
   constructor (options = {}) {
     // Enable object mode as EventSourceStream emits objects of shape
@@ -280,7 +281,7 @@ class EventSourceStream extends Transform {
 
   /**
    * @param {Buffer} line
-   * @param {EventStreamEvent} event
+   * @param {EventSourceStreamEvent} event
    */
   parseLine (line, event) {
     // If the line is empty (a blank line)
diff --git a/lib/web/eventsource/eventsource.js b/lib/web/eventsource/eventsource.js
index 60b4d842951..257b9573ef9 100644
--- a/lib/web/eventsource/eventsource.js
+++ b/lib/web/eventsource/eventsource.js
@@ -28,7 +28,8 @@ const defaultReconnectionTime = 3000
 
 /**
  * The readyState attribute represents the state of the connection.
- * @enum
+ * @typedef ReadyState
+ * @type {0|1|2}
  * @readonly
  * @see https://html.spec.whatwg.org/multipage/server-sent-events.html#dom-eventsource-readystate-dev
  */
@@ -80,9 +81,12 @@ class EventSource extends EventTarget {
     message: null
   }
 
-  #url = null
+  #url
   #withCredentials = false
 
+  /**
+   * @type {ReadyState}
+   */
   #readyState = CONNECTING
 
   #request = null
@@ -98,7 +102,7 @@ class EventSource extends EventTarget {
   /**
    * Creates a new EventSource object.
    * @param {string} url
-   * @param {EventSourceInit} [eventSourceInitDict]
+   * @param {EventSourceInit} [eventSourceInitDict={}]
    * @see https://html.spec.whatwg.org/multipage/server-sent-events.html#the-eventsource-interface
    */
   constructor (url, eventSourceInitDict = {}) {
@@ -148,7 +152,7 @@ class EventSource extends EventTarget {
     // 7. If the value of eventSourceInitDict's withCredentials member is true,
     // then set corsAttributeState to Use Credentials and set ev's
     // withCredentials attribute to true.
-    if (eventSourceInitDict.withCredentials) {
+    if (eventSourceInitDict.withCredentials === true) {
       corsAttributeState = USE_CREDENTIALS
       this.#withCredentials = true
     }
@@ -189,7 +193,7 @@ class EventSource extends EventTarget {
   /**
    * Returns the state of this EventSource object's connection. It can have the
    * values described below.
-   * @returns {0|1|2}
+   * @returns {ReadyState}
    * @readonly
    */
   get readyState () {