@wordpress/compose/build/hooks/use-fixed-window-list/index.cjs

WordPress higher-order components (HOCs).

"use strict";
var __create = Object.create;
var __defProp = Object.defineProperty;
var __getOwnPropDesc = Object.getOwnPropertyDescriptor;
var __getOwnPropNames = Object.getOwnPropertyNames;
var __getProtoOf = Object.getPrototypeOf;
var __hasOwnProp = Object.prototype.hasOwnProperty;
var __export = (target, all) => {
  for (var name in all)
    __defProp(target, name, { get: all[name], enumerable: true });
};
var __copyProps = (to, from, except, desc) => {
  if (from && typeof from === "object" || typeof from === "function") {
    for (let key of __getOwnPropNames(from))
      if (!__hasOwnProp.call(to, key) && key !== except)
        __defProp(to, key, { get: () => from[key], enumerable: !(desc = __getOwnPropDesc(from, key)) || desc.enumerable });
  }
  return to;
};
var __toESM = (mod, isNodeMode, target) => (target = mod != null ? __create(__getProtoOf(mod)) : {}, __copyProps(
  // If the importer is in node compatibility mode or this is not an ESM
  // file that has been converted to a CommonJS file using a Babel-
  // compatible transform (i.e. "__esModule" has not been set), then set
  // "default" to the CommonJS "module.exports" for node compatibility.
  isNodeMode || !mod || !mod.__esModule ? __defProp(target, "default", { value: mod, enumerable: true }) : target,
  mod
));
var __toCommonJS = (mod) => __copyProps(__defProp({}, "__esModule", { value: true }), mod);

// packages/compose/src/hooks/use-fixed-window-list/index.ts
var use_fixed_window_list_exports = {};
__export(use_fixed_window_list_exports, {
  default: () => useFixedWindowList
});
module.exports = __toCommonJS(use_fixed_window_list_exports);
var import_element = require("@wordpress/element");
var import_dom = require("@wordpress/dom");
var import_keycodes = require("@wordpress/keycodes");
var import_use_event = __toESM(require("../use-event/index.cjs"));
var DEFAULT_INIT_WINDOW_SIZE = 30;
function useFixedWindowList(elementRef, itemHeight, totalItems, options) {
  const {
    windowOverscan,
    useWindowing = true,
    initWindowSize = DEFAULT_INIT_WINDOW_SIZE,
    expandedState
  } = options ?? {};
  const [fixedListWindow, setFixedListWindow] = (0, import_element.useState)(
    {
      visibleItems: initWindowSize,
      start: 0,
      end: initWindowSize,
      itemInView: (index) => {
        return index >= 0 && index <= initWindowSize;
      }
    }
  );
  const visibleItemsRef = (0, import_element.useRef)(initWindowSize);
  const isFirstMeasurementRef = (0, import_element.useRef)(true);
  const measureWindow = (0, import_use_event.default)((initRender) => {
    const scrollContainer = (0, import_dom.getScrollContainer)(elementRef.current);
    if (!scrollContainer) {
      return;
    }
    const visibleItems = Math.ceil(
      scrollContainer.clientHeight / itemHeight
    );
    visibleItemsRef.current = visibleItems;
    const isFirstMeasurement = isFirstMeasurementRef.current;
    isFirstMeasurementRef.current = false;
    const overscan = initRender ? visibleItems : windowOverscan ?? visibleItems;
    const firstViewableIndex = Math.floor(
      scrollContainer.scrollTop / itemHeight
    );
    const start = Math.max(0, firstViewableIndex - overscan);
    const end = Math.min(
      totalItems - 1,
      firstViewableIndex + visibleItems + overscan
    );
    setFixedListWindow((lastWindow) => {
      if (lastWindow.start <= start && lastWindow.end >= end) {
        return lastWindow;
      }
      if (isFirstMeasurement && lastWindow.start <= firstViewableIndex && lastWindow.end >= firstViewableIndex + visibleItems) {
        return lastWindow;
      }
      return {
        visibleItems,
        start,
        end,
        itemInView: (index) => {
          return start <= index && index <= end;
        }
      };
    });
  });
  const handleKeyDown = (0, import_use_event.default)(
    (event, scrollContainer) => {
      switch (event.keyCode) {
        case import_keycodes.HOME: {
          return scrollContainer.scrollTo({ top: 0 });
        }
        case import_keycodes.END: {
          return scrollContainer.scrollTo({
            top: totalItems * itemHeight
          });
        }
        case import_keycodes.PAGEUP: {
          return scrollContainer.scrollTo({
            top: scrollContainer.scrollTop - visibleItemsRef.current * itemHeight
          });
        }
        case import_keycodes.PAGEDOWN: {
          return scrollContainer.scrollTo({
            top: scrollContainer.scrollTop + visibleItemsRef.current * itemHeight
          });
        }
      }
    }
  );
  (0, import_element.useLayoutEffect)(() => {
    if (!useWindowing) {
      return;
    }
    measureWindow(true);
  }, [
    useWindowing,
    measureWindow,
    itemHeight,
    totalItems,
    windowOverscan,
    expandedState
  ]);
  (0, import_element.useLayoutEffect)(() => {
    if (!useWindowing) {
      return;
    }
    const scrollContainer = (0, import_dom.getScrollContainer)(elementRef.current);
    if (!scrollContainer) {
      return;
    }
    const { defaultView } = scrollContainer.ownerDocument;
    const onMeasure = () => measureWindow();
    const onKeyDown = (event) => handleKeyDown(event, scrollContainer);
    scrollContainer.addEventListener("scroll", onMeasure);
    defaultView?.addEventListener("resize", onMeasure);
    defaultView?.addEventListener("keydown", onKeyDown);
    return () => {
      scrollContainer.removeEventListener("scroll", onMeasure);
      defaultView?.removeEventListener("resize", onMeasure);
      defaultView?.removeEventListener("keydown", onKeyDown);
    };
  }, [
    useWindowing,
    elementRef,
    itemHeight,
    totalItems,
    expandedState,
    measureWindow,
    handleKeyDown
  ]);
  return [fixedListWindow, setFixedListWindow];
}
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