/**
 * 函数防抖
 * @param {Function} func
 * @param {number} delay
 * @param {boolean} immediate
 * @return {*}
 */

 export function debounce(func, delay, immediate = false) {
  let timer,
    context = this;
  return (...args) => {
    if (immediate) {
      func.apply(context, args);
      immediate = false;
      return;
    }
    clearTimeout(timer);
    timer = setTimeout(() => {
      func.apply(context, args);
    }, delay);
  };
}