JavaScript语法小示例

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JavaScript语法小示例
JavaScript语法小示例 B2B网络软件

// JavaScript 高级功能综合示例
// 基于 AIWROK 软件技术文档中的 JavaScript 语句说明
// 包含基础概念和高级功能的完整演示
// ==================== 第一部分：基础概念 ====================
console.log("\n========== JavaScript 基础概念演示开始 ==========");
sleep.second(秒=2);
// 1. JavaScript 语句 - 用分号分隔的命令
console.log("\n【1】JavaScript 语句示例");
var x = 5 + 6; // 数字运算
var y = x * 10; // 表达式计算
console.log("x = " + x + ", y = " + y);
sleep.second(秒=2);
// 2. JavaScript 关键字使用示例
console.log("\n【2】JavaScript 关键字使用示例");
var firstName = "John"; // var 关键字声明变量
var lastName = "Doe"; // 字符串赋值
var age = 30; // 数字赋值
var isActive = true; // 布尔值
console.log("姓名: " + firstName + " " + lastName + ", 年龄: " + age + ", 激活状态: " + isActive);
sleep.second(秒=2);
// 3. JavaScript 注释示例
// 这是单行注释，不会被执行
/*
这是多行注释
也不会被执行
*/
// 4. JavaScript 数据类型示例
console.log("\n【4】JavaScript 数据类型示例");
var length = 16; // Number 类型
var points = x * 10; // Number 通过表达式
var fullName = firstName + " " + lastName; // String 字符串拼接
var hobbies = ["阅读", "编程", "运动"]; // Array 数组
var person = { // Object 对象
firstName: firstName,
lastName: lastName,
age: age,
isActive: isActive
};
console.log("长度: " + length + ", 分数: " + points);
console.log("全名: " + fullName);
console.log("爱好数量: " + hobbies.length);
sleep.second(秒=2);
// 5. 数据类型操作示例
console.log("\n【5】数据类型操作示例");
var numStr = 16 + "Volvo"; // 数字与字符串拼接结果为 "16Volvo"
console.log("数字与字符串拼接结果: " + numStr);
sleep.second(秒=2);
// 6. JavaScript 函数示例
console.log("\n【6】JavaScript 函数示例");
function calculateArea(width, height) {
return width * height; // 返回面积计算结果
}
function greetUser(name) {
return "你好, " + name + "!"; // 返回问候语
}
// 调用函数
var area = calculateArea(5, 10);
var greeting = greetUser(firstName);
console.log("矩形面积 (5x10): " + area);
console.log(greeting);
sleep.second(秒=2);
// 7. 大小写敏感性示例
console.log("\n【7】大小写敏感性示例");
var myVariable = "小写变量";
var MyVariable = "大写开头变量";
// 注意：myVariable 和 MyVariable 是两个不同的变量
console.log("myVariable: " + myVariable);
console.log("MyVariable: " + MyVariable);
console.log("两个变量不同: " + (myVariable !== MyVariable));
sleep.second(秒=2);
// 8. 更多关键字使用示例
console.log("\n【8】控制流关键字示例");
if (age >= 18) {
console.log("年龄 " + age + " - 成年人");
} else {
console.log("年龄 " + age + " - 未成年人");
}
console.log("\n遍历爱好列表:");
for (var i = 0; i < hobbies.length; i++) {
console.log(" 爱好 " + (i+1) + ": " + hobbies[i]);
}
sleep.second(秒=2);
// 9. switch 语句示例
console.log("\n【9】switch 语句示例");
var day = 3;
var dayName;
switch (day) {
case 1:
dayName = "星期一";
break;
case 2:
dayName = "星期二";
break;
case 3:
dayName = "星期三";
break;
default:
dayName = "其他日期";
}
console.log("今天是: " + dayName);
sleep.second(秒=2);
// 10. try-catch 错误处理示例
console.log("\n【10】try-catch 错误处理示例");
try {
var result = undefinedVariable + 10; // 这会引发错误
} catch (error) {
console.log("捕获到错误: " + error.message);
console.log("错误处理成功！");
}
sleep.second(秒=2);
// 11. 数组操作方法
console.log("\n【11】数组操作方法示例");
var numbers = [1, 2, 3, 4, 5];
console.log("原始数组: " + numbers.join(", "));
numbers.push(6); // 添加元素
console.log("push后: " + numbers.join(", "));
numbers.pop(); // 移除最后一个元素
console.log("pop后: " + numbers.join(", "));
sleep.second(秒=2);
// 12. 对象方法示例
console.log("\n【12】对象方法示例");
person.getFullName = function() {
return this.firstName + " " + this.lastName;
};
console.log("完整姓名: " + person.getFullName());
console.log("人员信息: " + JSON.stringify(person));
sleep.second(秒=2);
// ==================== 第二部分：高级功能 ====================
console.log("\n========== JavaScript 高级功能演示开始 ==========");
sleep.second(秒=2);
// 13. 闭包示例
console.log("\n【13】闭包示例");
function createCounter() {
var count = 0;
return {
increment: function() {
count++;
return count;
},
decrement: function() {
count--;
return count;
},
getCount: function() {
return count;
}
};
}
var counter = createCounter();
console.log("计数器初始值: " + counter.getCount());
console.log("递增后: " + counter.increment());
console.log("再递增: " + counter.increment());
console.log("递减后: " + counter.decrement());
sleep.second(秒=2);
// 14. 递归函数示例
console.log("\n【14】递归函数示例");
function factorial(n) {
if (n <= 1) return 1;
return n * factorial(n - 1);
}
console.log("5的阶乘: " + factorial(5));
console.log("10的阶乘: " + factorial(10));
sleep.second(秒=2);
// 15. 高阶函数示例
console.log("\n【15】高阶函数示例");
function applyOperation(arr, operation) {
var result = [];
for (var i = 0; i < arr.length; i++) {
result.push(operation(arr[i]));
}
return result;
}
var squaredNumbers = applyOperation([1, 2, 3, 4, 5], function(num) {
return num * num;
});
console.log("原始数组: [1, 2, 3, 4, 5]");
console.log("平方数组: " + squaredNumbers.join(", "));
sleep.second(秒=2);
// 16. 原型链示例
console.log("\n【16】原型链继承示例");
function Animal(name, type) {
this.name = name;
this.type = type;
}
Animal.prototype.speak = function() {
return this.name + " 发出了声音";
};
function Dog(name) {
Animal.call(this, name, "狗");
}
Dog.prototype = Object.create(Animal.prototype);
Dog.prototype.constructor = Dog;
Dog.prototype.bark = function() {
return this.name + " 汪汪叫";
};
var myDog = new Dog("旺财");
console.log(myDog.speak());
console.log(myDog.bark());
sleep.second(秒=2);
// 17. Promise 模拟（由于环境限制，使用回调方式）
console.log("\n【17】异步编程示例");
function asyncOperation(data, callback) {
setTimeout(function() {
var result = "处理完成: " + data;
callback(null, result);
}, 100);
}
asyncOperation("测试数据", function(error, result) {
if (error) {
console.log("错误: " + error);
} else {
console.log(result);
}
});
sleep.second(秒=2);
// 18. 模块化模式
console.log("\n【18】模块化模式示例");
var MathUtils = (function() {
// 私有变量和方法
var PI = 3.14159265359;
function validateNumber(num) {
return typeof num === 'number' && !isNaN(num);
}
// 公共API
return {
circleArea: function(radius) {
if (!validateNumber(radius) || radius < 0) {
throw new Error("无效的半径值");
}
return PI * radius * radius;
},
rectangleArea: function(width, height) {
if (!validateNumber(width) || !validateNumber(height)) {
throw new Error("无效的尺寸值");
}
return width * height;
},
add: function(a, b) {
if (!validateNumber(a) || !validateNumber(b)) {
throw new Error("无效的数字参数");
}
return a + b;
}
};
})();
console.log("圆面积 (r=5): " + MathUtils.circleArea(5));
console.log("矩形面积 (5x10): " + MathUtils.rectangleArea(5, 10));
console.log("加法 (3+7): " + MathUtils.add(3, 7));
sleep.second(秒=2);
// 19. 事件模拟器
console.log("\n【19】事件系统示例");
var EventEmitter = function() {
this.events = {};
};
EventEmitter.prototype.on = function(event, listener) {
if (!this.events[event]) {
this.events[event] = [];
}
this.events[event].push(listener);
};
EventEmitter.prototype.emit = function(event) {
if (this.events[event]) {
var args = Array.prototype.slice.call(arguments, 1);
this.events[event].forEach(function(listener) {
listener.apply(null, args);
});
}
};
var emitter = new EventEmitter();
emitter.on('greet', function(name) {
console.log("欢迎, " + name + "!");
});
emitter.on('data', function(data) {
console.log("收到数据: " + data);
});
emitter.emit('greet', '用户');
emitter.emit('data', '重要信息');
sleep.second(秒=2);
// 20. 数据结构实现 - 栈
console.log("\n【20】栈 (Stack) 数据结构示例");
function Stack() {
this.items = [];
}
Stack.prototype.push = function(item) {
this.items.push(item);
};
Stack.prototype.pop = function() {
if (this.isEmpty()) {
return null;
}
return this.items.pop();
};
Stack.prototype.peek = function() {
if (this.isEmpty()) {
return null;
}
return this.items[this.items.length - 1];
};
Stack.prototype.isEmpty = function() {
return this.items.length === 0;
};
Stack.prototype.size = function() {
return this.items.length;
};
var stack = new Stack();
stack.push(1);
stack.push(2);
stack.push(3);
console.log("栈顶元素: " + stack.peek());
console.log("弹出元素: " + stack.pop());
console.log("栈大小: " + stack.size());
sleep.second(秒=2);
// 21. 数据结构实现 - 队列
console.log("\n【21】队列 (Queue) 数据结构示例");
function Queue() {
this.items = [];
}
Queue.prototype.enqueue = function(item) {
this.items.push(item);
};
Queue.prototype.dequeue = function() {
if (this.isEmpty()) {
return null;
}
return this.items.shift();
};
Queue.prototype.front = function() {
if (this.isEmpty()) {
return null;
}
return this.items[0];
};
Queue.prototype.isEmpty = function() {
return this.items.length === 0;
};
Queue.prototype.size = function() {
return this.items.length;
};
var queue = new Queue();
queue.enqueue("任务1");
queue.enqueue("任务2");
queue.enqueue("任务3");
console.log("队首任务: " + queue.front());
console.log("完成任务: " + queue.dequeue());
console.log("剩余任务数: " + queue.size());
sleep.second(秒=2);
// 22. 正则表达式示例
console.log("\n【22】正则表达式验证示例");
function validateEmail(email) {
var emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
return emailRegex.test(email);
}
function validatePhone(phone) {
var phoneRegex = /^1[3-9]\d{9}$/;
return phoneRegex.test(phone);
}
console.log("邮箱验证 test@example.com: " + validateEmail("test@example.com"));
console.log("手机号验证 13812345678: " + validatePhone("13812345678"));
sleep.second(秒=2);
// 23. JSON 操作示例
console.log("\n【23】JSON 数据处理示例");
var userData = {
id: 1,
name: "张三",
age: 25,
hobbies: ["读书", "游泳"],
address: {
city: "北京",
street: "长安街100号"
}
};
var jsonString = JSON.stringify(userData);
console.log("JSON字符串: " + jsonString);
var parsedData = JSON.parse(jsonString);
console.log("解析后的名字: " + parsedData.name);
console.log("解析后的城市: " + parsedData.address.city);
sleep.second(秒=2);
// 24. 字符串处理方法
console.log("\n【24】字符串处理方法示例");
var text = "Hello World JavaScript";
console.log("转大写: " + text.toUpperCase());
console.log("转小写: " + text.toLowerCase());
console.log("子字符串: " + text.substring(0, 5));
console.log("替换: " + text.replace("World", "宇宙"));
console.log("分割: " + text.split(" ").join("-"));
sleep.second(秒=2);
// 25. 日期和时间处理
console.log("\n【25】日期和时间处理示例");
var now = new Date();
console.log("当前时间: " + now.toLocaleString());
console.log("年份: " + now.getFullYear());
console.log("月份: " + (now.getMonth() + 1));
console.log("日期: " + now.getDate());
console.log("小时: " + now.getHours());
console.log("分钟: " + now.getMinutes());
console.log("秒数: " + now.getSeconds());
sleep.second(秒=2);
// 26. Map 数据结构
console.log("\n【26】Map 数据结构示例");
function CustomMap() {
this.keys = [];
this.values = [];
}
CustomMap.prototype.set = function(key, value) {
var index = this.keys.indexOf(key);
if (index !== -1) {
this.values[index] = value;
} else {
this.keys.push(key);
this.values.push(value);
}
};
CustomMap.prototype.get = function(key) {
var index = this.keys.indexOf(key);
if (index !== -1) {
return this.values[index];
}
return undefined;
};
CustomMap.prototype.has = function(key) {
return this.keys.indexOf(key) !== -1;
};
CustomMap.prototype.delete = function(key) {
var index = this.keys.indexOf(key);
if (index !== -1) {
this.keys.splice(index, 1);
this.values.splice(index, 1);
return true;
}
return false;
};
CustomMap.prototype.size = function() {
return this.keys.length;
};
var map = new CustomMap();
map.set("name", "李四");
map.set("age", 28);
map.set("city", "上海");
console.log("Map中获取name: " + map.get("name"));
console.log("Map中是否存在age: " + map.has("age"));
console.log("Map大小: " + map.size());
map.delete("city");
console.log("删除city后Map大小: " + map.size());
sleep.second(秒=2);
// 27. Set 数据结构
console.log("\n【27】Set 数据结构示例");
function CustomSet() {
this.items = {};
}
CustomSet.prototype.add = function(value) {
this.items[value] = value;
};
CustomSet.prototype.has = function(value) {
return this.items.hasOwnProperty(value);
};
CustomSet.prototype.delete = function(value) {
if (this.has(value)) {
delete this.items[value];
return true;
}
return false;
};
CustomSet.prototype.size = function() {
return Object.keys(this.items).length;
};
CustomSet.prototype.values = function() {
return Object.keys(this.items);
};
var set = new CustomSet();
set.add(1);
set.add(2);
set.add(3);
set.add(2); // 重复值不会添加
console.log("Set中的值: " + set.values().join(", "));
console.log("Set大小: " + set.size());
console.log("是否包含2: " + set.has(2));
set.delete(1);
console.log("删除1后Set大小: " + set.size());
sleep.second(秒=2);
// 28. 观察者模式
console.log("\n【28】观察者模式示例");
function Subject() {
this.observers = [];
}
Subject.prototype.addObserver = function(observer) {
this.observers.push(observer);
};
Subject.prototype.removeObserver = function(observer) {
var index = this.observers.indexOf(observer);
if (index > -1) {
this.observers.splice(index, 1);
}
};
Subject.prototype.notify = function(data) {
this.observers.forEach(function(observer) {
observer.update(data);
});
};
function Observer(name) {
this.name = name;
}
Observer.prototype.update = function(data) {
console.log(this.name + " 收到更新: " + data);
};
var subject = new Subject();
var observer1 = new Observer("观察者1");
var observer2 = new Observer("观察者2");
subject.addObserver(observer1);
subject.addObserver(observer2);
subject.notify("状态改变");
sleep.second(秒=2);
// 29. 工厂模式
console.log("\n【29】工厂模式示例");
function createUser(type, name, age) {
var user = {
name: name,
age: age,
type: type
};
if (type === "admin") {
user.permissions = ["read", "write", "delete"];
} else if (type === "user") {
user.permissions = ["read"];
}
user.getInfo = function() {
return this.name + " (" + this.type + "), 年龄: " + this.age;
};
return user;
}
var admin = createUser("admin", "管理员", 35);
var regularUser = createUser("user", "普通用户", 25);
console.log(admin.getInfo());
console.log("管理员权限: " + admin.permissions.join(", "));
console.log(regularUser.getInfo());
console.log("普通用户权限: " + regularUser.permissions.join(", "));
sleep.second(秒=2);
// 30. 装饰器模式
console.log("\n【30】装饰器模式示例");
function Coffee(price) {
this.price = price;
}
Coffee.prototype.cost = function() {
return this.price;
};
function MilkDecorator(coffee) {
this.coffee = coffee;
}
MilkDecorator.prototype.cost = function() {
return this.coffee.cost() + 5;
};
function SugarDecorator(coffee) {
this.coffee = coffee;
}
SugarDecorator.prototype.cost = function() {
return this.coffee.cost() + 2;
};
var basicCoffee = new Coffee(10);
var milkCoffee = new MilkDecorator(basicCoffee);
var sweetMilkCoffee = new SugarDecorator(milkCoffee);
console.log("基础咖啡价格: " + basicCoffee.cost());
console.log("加奶咖啡价格: " + milkCoffee.cost());
console.log("加糖加奶咖啡价格: " + sweetMilkCoffee.cost());
sleep.second(秒=2);
// 输出所有示例结果总结
console.log("\n========== JavaScript 演示完成 ==========");
console.log("\n已演示以下功能:");
console.log("1. 基础语法和数据类型");
console.log("2. 函数和闭包");
console.log("3. 面向对象编程");
console.log("4. 异步编程模式");
console.log("5. 模块化设计");
console.log("6. 事件系统");
console.log("7. 数据结构实现 (栈、队列、Map、Set)");
console.log("8. 正则表达式");
console.log("9. JSON处理");
console.log("10. 字符串和日期处理");
console.log("11. 设计模式应用 (工厂、观察者、装饰器)");
console.log("\n总计: 30个功能模块演示完成！");
console.log("\n========== 演示结束 ==========");

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