使用代理实现单例

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class MyVideo {
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  constructor(a, b) {
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    this.a = a;
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    this.b = b;
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  }
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  sayHello() {
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    console.log("hello");
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  }
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}
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function isSame(value1, value2) {
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  if (value1.length !== value2.length) {
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    return false;
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  }
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  for (let i = 0; i < value1.length; i++) {
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    if (value1[i] !== value2[i]) {
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      return false;
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    }
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  }
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  return true;
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}
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function singaleton(className) {
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  let ins, parameters;
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  return new Proxy(className, {
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    construct(target, args) {
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      if (!ins) {
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        ins = new target(target, ...args);
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        parameters = args;
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      }
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      if (!isSame(parameters, args)) {
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        throw new Error("参数不一致");
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      }
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      return ins;
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    },
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  });
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}
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const Video = singaleton(MyVideo);
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const v1 = new Video();
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const v2 = new Video();
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console.log("v1 === v2:", v1 === v2);

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v1 === v2: true