feat：手写代码

src/.vuepress/public/demo/js/handwritten.js

@@ -0,0 +1,144 @@
+// function throttle(func, limit) {
+//   let inThrottle;
+//   return function (...args) {
+//     const context = this;
+//     if (inThrottle) return;
+//     func.apply(context, args);
+//     inThrottle = true;
+//     setTimeout(() => (inThrottle = false), limit);
+//   };
+// }
+
+function debounce(func, wait = 50) {
+  let timer;
+  return function (...args) {
+    if (timer) clearTimeout(timer);
+    timer = setTimeout(() => {
+      func.apply(this, args);
+    }, wait);
+  };
+}
+
+const throttle = (func, limit) => {
+  let lastTime = 0;
+  return function (...args) {
+    let now = +new Date();
+    if (now - lastTime > limit) {
+      lastTime = now;
+      func.apply(this, args);
+    }
+  };
+};
+
+// setInterval(
+//   throttle(() => {
+//     console.log(1);
+//   }, 2000),
+//   1
+// );
+
+// setInterval(
+//   debounce(() => {
+//     console.log(1);
+//   }, 500),
+//   600
+// );
+
+Function.prototype.myCall = function (context = global, ...args) {
+  if (typeof this !== "function") {
+    throw new TypeError("error");
+  }
+  const fn = Symbol();
+  context[fn] = this;
+  const result = context[fn](...args);
+  delete context[fn];
+  return result;
+};
+
+Function.prototype.myApply = function (context = global, args) {
+  if (typeof this !== "function") {
+    throw new TypeError("error");
+  }
+  const fn = Symbol();
+  context[fn] = this;
+  let result;
+  if (Array.isArray(args)) {
+    result = context[fn](...args);
+  } else {
+    result = context[fn]();
+  }
+  delete context[fn];
+  return result;
+};
+
+const obj = { a: 9 };
+const f = function () {
+  console.log(this.a);
+  return this;
+};
+console.log(f() == global);
+console.log(f.myCall(obj));
+console.log(f.myApply(obj));
+
+Function.prototype.myBind = function (context) {
+  // 判断调研对象是否是函数
+  if (typeof this !== "function") {
+    throw new TypeError("Error");
+  }
+  // 获取参数
+  const args = [...arguments].slice(1),
+    fn = this;
+  return function Fn() {
+    console.log("this instanceof Fn", this instanceof Fn);
+    return fn.apply(
+      this instanceof Fn ? new fn(...arguments) : context,
+      args.concat(...arguments)
+    );
+  };
+};
+
+function fn(...args) {
+  console.log(this, args);
+}
+// let obj = {
+//   myname: "张三",
+// };
+
+// const bindFn = fn.myBind(obj); // this 也会变成传入的obj ，bind不是立即执行需要执行一次
+// new bindFn(1, 2); // this指向obj
+// fn.myBind(obj)(3); // this 也会变成传入的obj ，bind不是立即执行需要执行一次
+// fn(1, 2); // this指向window
+
+function myInstanceof(target, origin) {
+  const proto = Object.getPrototypeOf(target);
+  if (proto) {
+    if (proto == origin.prototype) {
+      return true;
+    } else {
+      return myInstanceof(proto, origin);
+    }
+  } else {
+    return false;
+  }
+}
+
+// function Car() {}
+// const car = new Car();
+// console.log(myInstanceof(car, Car));
+
+function myNew(Func, ...args) {
+  // 创建新对象
+  const obj = {};
+  // 执行构造函数对象
+  obj.__proto__ = Func.prototype;
+  // 构造函数的this指向新对象
+  let result = Func.apply(obj, args);
+  // 根据返回值判断
+  return result instanceof Object ? result : obj;
+}
+
+// function Person(name) {
+//   this.name = name;
+// }
+// const person = myNew(Person, "宋兴国");
+// console.log(person);