Question

/**
 * @param { function } func
 * @param { number } wait 延迟执行毫秒数
 * @param { boolean } immediate  true 表立即执行，false 表非立即执行
 */
export function debounce(func,wait,immediate) {
  let timeout;
  return function () {
    let context = this;
    let args = arguments;

    if (timeout) clearTimeout(timeout);
    if (immediate) {
      let callNow = !timeout;
      timeout = setTimeout(() => {
        timeout = null;
      }, wait);
      if (callNow) func.apply(context, args)
    }
    else {
      timeout = setTimeout(() => {
        func.apply(context, args)
      }, wait);
    }
  }
}