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mohammadhzp/dummy.js

Created February 6, 2023 09:25
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Singleton Impl in Javascript. `singleton.js` is the file you really need. the rest is there to make a running exmaple.
Raw
dummy.js
class Dummy extends Singleton {
constructor() {
super();
this.i = 0;
}
incr() { ++this.i; }
}
Raw
index.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Example demonstrating Singleton in JS</title>
</head>
<body>
<h2>Checkout console</h2>
<script src="singleton.js"></script>
<script src="dummy.js"></script>
<script src="main.js"></script>
</body>
</html>
Raw
main.js
Dummy.instance().incr();
Dummy.instance().incr();
let obj = Dummy.instance();
obj.incr();
console.log((Dummy.instance()).i); // 3
console.log(obj.i); // 3
console.log((Dummy.instance()) === obj); // true
Raw
singleton.js
class Singleton {
static _instance = null;
static instance() {
if (this._instance === null) {
this._instance = new this();
}
return this._instance;
}
}
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