@iicoding/utils/dist/esm/helper/debounce.js

Browser 端 - 类型判断 - 类似 koa 的异步compose - sleep - 扩展对象属性 - 扩展 storage 对象功能

import { isObject } from "../index";
import root from "../global";
export function debounce(func, wait, options) {
  var lastArgs;
  var lastThis;
  var maxWait;
  var result;
  var timerId;
  var lastCallTime;
  var lastInvokeTime = 0;
  var leading = false;
  var maxing = false;
  var trailing = true;

  // Bypass `requestAnimationFrame` by explicitly setting `wait=0`.
  var useRAF = !wait && wait !== 0 && typeof root.requestAnimationFrame === 'function';
  if (typeof func !== 'function') {
    throw new TypeError('Expected a function');
  }
  wait = +wait || 0;
  if (isObject(options)) {
    leading = !!options.leading;
    maxing = 'maxWait' in options;
    // @ts-ignore
    maxWait = maxing ? Math.max(+options.maxWait || 0, wait) : maxWait;
    trailing = 'trailing' in options ? !!options.trailing : trailing;
  }
  function invokeFunc(time) {
    var args = lastArgs;
    var thisArg = lastThis;
    lastArgs = lastThis = undefined;
    lastInvokeTime = time;
    result = func.apply(thisArg, args);
    return result;
  }
  function startTimer(pendingFunc, milliseconds) {
    if (useRAF) {
      root.cancelAnimationFrame(timerId);
      return root.requestAnimationFrame(pendingFunc);
    }
    return setTimeout(pendingFunc, milliseconds);
  }
  function cancelTimer(id) {
    if (useRAF) {
      root.cancelAnimationFrame(id);
      return;
    }
    clearTimeout(id);
  }

  // @ts-ignore
  // eslint-disable-next-line @typescript-eslint/no-unused-vars
  function leadingEdge(time) {
    // Reset any `maxWait` timer.
    lastInvokeTime = time;
    // Start the timer for the trailing edge.
    timerId = startTimer(timerExpired, wait);
    // Invoke the leading edge.
    return leading ? invokeFunc(time) : result;
  }
  function remainingWait(time) {
    var timeSinceLastCall = time - lastCallTime;
    var timeSinceLastInvoke = time - lastInvokeTime;
    var timeWaiting = wait - timeSinceLastCall;
    return maxing ? Math.min(timeWaiting, maxWait - timeSinceLastInvoke) : timeWaiting;
  }
  function shouldInvoke(time) {
    var timeSinceLastCall = time - lastCallTime;
    var timeSinceLastInvoke = time - lastInvokeTime;

    // Either this is the first call, activity has stopped and we're at the
    // trailing edge, the system time has gone backwards and we're treating
    // it as the trailing edge, or we've hit the `maxWait` limit.
    return lastCallTime === undefined || timeSinceLastCall >= wait || timeSinceLastCall < 0 || maxing && timeSinceLastInvoke >= maxWait;
  }
  function timerExpired() {
    var time = Date.now();
    if (shouldInvoke(time)) {
      return trailingEdge(time);
    }
    // Restart the timer.
    timerId = startTimer(timerExpired, remainingWait(time));
    return undefined;
  }
  function trailingEdge(time) {
    // @ts-ignore
    timerId = undefined;

    // Only invoke if we have `lastArgs` which means `func` has been
    // debounced at least once.
    if (trailing && lastArgs) {
      return invokeFunc(time);
    }
    lastArgs = lastThis = undefined;
    return result;
  }
  function cancel() {
    if (timerId !== undefined) {
      cancelTimer(timerId);
    }
    lastInvokeTime = 0;
    // @ts-ignore
    lastArgs = lastCallTime = lastThis = timerId = undefined;
  }
  function flush() {
    return timerId === undefined ? result : trailingEdge(Date.now());
  }
  function pending() {
    return timerId !== undefined;
  }

  // @ts-ignore
  // eslint-disable-next-line @typescript-eslint/no-unused-vars
  function debounced() {}
  debounced.cancel = cancel;
  debounced.flush = flush;
  debounced.pending = pending;
  return debounced;
}
export default debounce;