How to write anti-shake (debounce) and throttle (throttle) functions in Vue

key point:

• The writing method of vue is a bit different from ordinary ones, because this of vue is not only the current component object, but also inherits the vue object upwards (the difference can be seen below)
• call and apply can only inherit from the parent, not deep inheritance
• Because deep inheritance requires recursive or multi-layer nested functions, the code volume is large and difficult to maintain, so the following method is recommended

1. Anti-shake (debounce)

• Meaning: After the high-frequency time is triggered, the function will only be executed once within n seconds. If the high-frequency time is triggered again within n seconds, the time will be recalculated.

It is a continuous process. For example, it is limited to 1s, executed once, and the next execution is 1s, that is, the function is executed when the user stops the operation; as long as the operation is not stopped, the operation in the function will never be executed

• Usage scenario: anti-shake is often applied to users to search and input to save request resources, and anti-shake is only triggered once when an event windowis triggeredresize
• code:

/**
 * @description 函数防抖 触发高频时间后n秒内函数只会执行一次,如果n秒内高频时间再次触发,则重新计算时间。
 * @param {Function} func 需要执行的函数
 * @param {Number} wait 间隔时间 默认200ms
 * @param {Boolean} immediate  是否立即执行 true(默认) 表立即执行，false 表非立即执行
 * @return {*}
 * @author liuxin
 */
export function VueDebounce(func, wait = 200, immediate = true) {
    let timeout = null;  // 定时器
    return function () {
        let that = this, // this对象
            args = arguments; // 参数
        if (timeout) clearTimeout(timeout);
        if (immediate === true) { // 立即执行
            var callNow = !timeout;
            timeout = setTimeout(() => {
                timeout = null;
            }, wait)
            if (callNow) {
                // func.apply(that, args); // 普通用法 vue3用法
                that[func](...args); // vue2用法
            }
        }
        else { // 非立即执行
            timeout = setTimeout(() => {
                // func.apply(this, args); // 普通用法 vue3用法
                that[func](...args); // vue2用法
            }, wait);
        }
    }
}

• Usage Vue2

methods: {
    /**
     * 点击事件 函数防抖
     * 用法：<el-button @click="debounceHandel">点击测试</el-button>
     */
    debounceHandel: VueDebounce("handlerFunc"),

    /**
     * 点击事件：真正执行的函数
     */
    handlerFunc(type) {
      console.log("测试防抖事件");
      this.$emit("click","这是参数"); // 如果用普通用法，则这里会找不到$emit，因为this还往上继承了vue的对象
    },
  }

• Usage vue3

<el-button type="primary" size="default" @click="cleanHandle">测试防抖</el-button>

export default {
  setup() {
    const state = reactive({
    });

    /**
     * @description: 一秒执行一次
     * @Author: liuxin
     */
    const cleanHandle = VueDebounce(() => {
      scoket.send(
        JSON.stringify({
          api: "clear_count",
        })
      );
    }, 1000);

    return {
      ...toRefs(state),
      cleanHandle,
    };
  },
};

2. Throttle

• Meaning: High-frequency time trigger, but it will only be executed once in n seconds, so throttling will dilute the execution frequency of the function. . It is a fixed process. If it is limited to 1s, it will only be executed once within 1s. No matter what, the corresponding operation will be executed within 1s.
• Usage scenario: Similar to the anti-shake usage scenario, the key is that feedback is required within a fixed time (1s), and feedback usage throttling is required, that is: regardless of whether the user stops the operation, the function operation will be executed at a fixed time
• Code: The usage is consistent with the function anti-shake

import { ElMessage } from "element-plus";
import "element-plus/es/components/message/style/css"
/**
 * @description 函数节流
 * @param {Function} func 函数
 * @param {Number} wait 延迟执行毫秒数,默认200
 * @param {Number} type 1 表时间戳版，2 表定时器版
 */
function VueThrottle(func, wait=200 ,type) {
    if(type===1){
        let previous = 0;
    }else if(type===2){
        let timeout;
    }
    return function() {
        let that= this;
        let args = arguments;
        if(type===1){
            let now = Date.now();

            if (now - previous > wait) {
                // func.apply(that, args); // 普通用法
                that[func](...args); // vue用法
                previous = now;
                ElMessage.closeAll(); // 关闭所有弹窗
            }
            else {
                ElMessage.error("操作太频繁了哦，稍后再试");
            }
        }else if(type===2){
            if (!timeout) {
                timeout = setTimeout(() => {
                    timeout = null;
                    // func.apply(that, args)
                    that[func](...args); // vue用法
                    ElMessage.closeAll();// 关闭所有弹窗
                }, wait)
            }
            else {
                ElMessage.error("操作太频繁了哦，稍后再试");
            }
        }
    }
}