Method constructor

frontend/src/polyfill.ts:9–15

(target: T)

      readonly [Symbol.toStringTag] = "WeakRef";

      constructor(target: T) {
        if (typeof target !== "object" || target === null) {
          throw new TypeError("WeakRef target must be an object.");
        }
        this.target = target;
        this.targetMap.set(this, target);
      }

      deref(): T | undefined {
        const target = this.targetMap.get(this);