@tanstack/query-core/build/modern/focusManager.js

The framework agnostic core that powers TanStack Query

// src/focusManager.ts
import { Subscribable } from "./subscribable.js";
import { isServer } from "./utils.js";
var FocusManager = class extends Subscribable {
  #focused;
  #cleanup;
  #setup;
  constructor() {
    super();
    this.#setup = (onFocus) => {
      if (!isServer && window.addEventListener) {
        const listener = () => onFocus();
        window.addEventListener("visibilitychange", listener, false);
        return () => {
          window.removeEventListener("visibilitychange", listener);
        };
      }
      return;
    };
  }
  onSubscribe() {
    if (!this.#cleanup) {
      this.setEventListener(this.#setup);
    }
  }
  onUnsubscribe() {
    if (!this.hasListeners()) {
      this.#cleanup?.();
      this.#cleanup = void 0;
    }
  }
  setEventListener(setup) {
    this.#setup = setup;
    this.#cleanup?.();
    this.#cleanup = setup((focused) => {
      if (typeof focused === "boolean") {
        this.setFocused(focused);
      } else {
        this.onFocus();
      }
    });
  }
  setFocused(focused) {
    const changed = this.#focused !== focused;
    if (changed) {
      this.#focused = focused;
      this.onFocus();
    }
  }
  onFocus() {
    const isFocused = this.isFocused();
    this.listeners.forEach((listener) => {
      listener(isFocused);
    });
  }
  isFocused() {
    if (typeof this.#focused === "boolean") {
      return this.#focused;
    }
    return globalThis.document?.visibilityState !== "hidden";
  }
};
var focusManager = new FocusManager();
export {
  FocusManager,
  focusManager
};
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