@kcuf-hook/use-debounced/dist/cjs/hook/use-debounced-callback.js

React hook - useDebounced/useThrottled.

"use strict";

var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault").default;
Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = useDebouncedCallback;
var _toConsumableArray2 = _interopRequireDefault(require("@babel/runtime/helpers/toConsumableArray"));
var _react = require("react");
var _useIsUnmounted = _interopRequireDefault(require("@kcuf-hook/use-is-unmounted"));
var _util = require("../util");
function useDebouncedCallback(fn, options) {
  var refFn = (0, _react.useRef)(fn);
  var refArgs = (0, _react.useRef)(null); // 上次调用 `fn` 的参数列表，执行后会被清空
  var refTimeCalled = (0, _react.useRef)(0); // 上次调用 `fn` 的时间（但不一定执行）
  var refTimeInvoked = (0, _react.useRef)(0); // 上次真正执行 `fn` 的时间
  var refTimerId = (0, _react.useRef)(null);
  var isUnmounted = (0, _useIsUnmounted.default)();
  var _resolveOptions = (0, _util.resolveOptions)(options),
    delay = _resolveOptions.delay,
    delayMax = _resolveOptions.delayMax,
    immediate = _resolveOptions.immediate;
  refFn.current = fn; // always fresh

  (0, _react.useEffect)(function () {
    return function () {
      if (refTimerId.current) {
        clearTimeout(refTimerId.current);
      }
      refTimerId.current = null;
    };
  }, []);
  return (0, _react.useMemo)(function () {
    function invokeFn() {
      var args = refArgs.current;
      if (args) {
        refArgs.current = null;
        refTimeInvoked.current = Date.now();
        refFn.current.apply(refFn, (0, _toConsumableArray2.default)(args));
      }
    }
    function startTimer(pendingFunc, wait) {
      if (refTimerId.current) {
        clearTimeout(refTimerId.current);
      }
      refTimerId.current = setTimeout(pendingFunc, wait);
    }
    function timerExpired() {
      if (isUnmounted()) {
        return;
      }
      if (Date.now() - refTimeCalled.current >= delay) {
        refTimerId.current = null;
        invokeFn();
        return;
      }
      var time = Date.now();
      var timeSinceLastCall = time - refTimeCalled.current;
      var timeSinceLastInvoke = time - refTimeInvoked.current;
      var timeWaiting = delay - timeSinceLastCall;
      var remainingWait = delayMax >= delay ? Math.min(timeWaiting, delayMax - timeSinceLastInvoke) : timeWaiting;
      startTimer(timerExpired, remainingWait);
    }
    function callFn() {
      var time = Date.now();
      for (var _len = arguments.length, args = new Array(_len), _key = 0; _key < _len; _key++) {
        args[_key] = arguments[_key];
      }
      refArgs.current = args;
      refTimeCalled.current = time;
      if (immediate && !refTimerId.current) {
        invokeFn();
      }
      if (delayMax >= delay && time - refTimeInvoked.current >= delayMax) {
        invokeFn();
        startTimer(timerExpired, delay);
      }
      if (!refTimerId.current) {
        startTimer(timerExpired, delay);
      }
    }
    return callFn;
  }, [delay, delayMax, immediate, isUnmounted]);
}