Add WeakRef and FinalizationRegistry article by WOLFRIEND · Pull Request #3609 · javascript-tutorial/en.javascript.info

javascript-tutorial

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		.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;
		}

Original file line number	Diff line number	Diff line change
		@@ -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>

Original file line number	Diff line number	Diff line change
		@@ -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);
		};

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