Merge pull request javascript-tutorial#3609 from WOLFRIEND/master

Add WeakRef and FinalizationRegistry article
pmaingi · Nov 15, 2023 · 5ab1ce2 · 5ab1ce2
2 parents 285083f + 8ab6b39
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diff --git a/1-js/99-js-misc/07-weakref-finalizationregistry/article.md b/1-js/99-js-misc/07-weakref-finalizationregistry/article.md
diff --git a/1-js/99-js-misc/07-weakref-finalizationregistry/google-chrome-developer-tools.png b/1-js/99-js-misc/07-weakref-finalizationregistry/google-chrome-developer-tools.png
diff --git a/1-js/99-js-misc/07-weakref-finalizationregistry/weakref-dom.view/index.css b/1-js/99-js-misc/07-weakref-finalizationregistry/weakref-dom.view/index.css
@@ -0,0 +1,49 @@
+.app {
+    display: flex;
+    flex-direction: column;
+    gap: 16px;
+}
+
+.start-messages {
+    width: fit-content;
+}
+
+.window {
+    width: 100%;
+    border: 2px solid #464154;
+    overflow: hidden;
+}
+
+.window__header {
+    position: sticky;
+    padding: 8px;
+    display: flex;
+    justify-content: space-between;
+    align-items: center;
+    background-color: #736e7e;
+}
+
+.window__title {
+    margin: 0;
+    font-size: 24px;
+    font-weight: 700;
+    color: white;
+    letter-spacing: 1px;
+}
+
+.window__button {
+    padding: 4px;
+    background: #4f495c;
+    outline: none;
+    border: 2px solid #464154;
+    color: white;
+    font-size: 16px;
+    cursor: pointer;
+}
+
+.window__body {
+    height: 250px;
+    padding: 16px;
+    overflow: scroll;
+    background-color: #736e7e33;
+}
diff --git a/1-js/99-js-misc/07-weakref-finalizationregistry/weakref-dom.view/index.html b/1-js/99-js-misc/07-weakref-finalizationregistry/weakref-dom.view/index.html
@@ -0,0 +1,28 @@
+<!DOCTYPE HTML>
+<html lang="en">
+
+<head>
+  <meta charset="utf-8">
+  <link rel="stylesheet" href="index.css">
+  <title>WeakRef DOM Logger</title>
+</head>
+
+<body>
+
+<div class="app">
+  <button class="start-messages">Start sending messages</button>
+  <div class="window">
+    <div class="window__header">
+      <p class="window__title">Messages:</p>
+      <button class="window__button">Close</button>
+    </div>
+    <div class="window__body">
+      No messages.
+    </div>
+  </div>
+</div>
+
+
+<script type="module" src="index.js"></script>
+</body>
+</html>
diff --git a/1-js/99-js-misc/07-weakref-finalizationregistry/weakref-dom.view/index.js b/1-js/99-js-misc/07-weakref-finalizationregistry/weakref-dom.view/index.js
@@ -0,0 +1,24 @@
+const startMessagesBtn = document.querySelector('.start-messages'); // (1)
+const closeWindowBtn = document.querySelector('.window__button'); // (2)
+const windowElementRef = new WeakRef(document.querySelector(".window__body")); // (3)
+
+startMessagesBtn.addEventListener('click', () => { // (4)
+    startMessages(windowElementRef);
+    startMessagesBtn.disabled = true;
+});
+
+closeWindowBtn.addEventListener('click', () =>  document.querySelector(".window__body").remove()); // (5)
+
+
+const startMessages = (element) => {
+    const timerId = setInterval(() => { // (6)
+        if (element.deref()) { // (7)
+            const payload = document.createElement("p");
+            payload.textContent = `Message: System status OK: ${new Date().toLocaleTimeString()}`;
+            element.deref().append(payload);
+        } else { // (8)
+            alert("The element has been deleted."); // (9)
+            clearInterval(timerId);
+        }
+    }, 1000);
+};
diff --git a/.../99-js-misc/07-weakref-finalizationregistry/weakref-finalizationregistry-01.svg b/.../99-js-misc/07-weakref-finalizationregistry/weakref-finalizationregistry-01.svg
diff --git a/.../99-js-misc/07-weakref-finalizationregistry/weakref-finalizationregistry-02.svg b/.../99-js-misc/07-weakref-finalizationregistry/weakref-finalizationregistry-02.svg