消息推送系统

// 创建一个消息类

class Message {

constructor(id, content) {

this.id = id;

this.content = content;

}

}

// 创建一个消息管理器类

class MessageManager {

constructor() {

this.messages = [];

}

addMessage(message) {

this.messages.push(message);

}

removeMessage(id) {

this.messages = this.messages.filter(msg => msg.id !== id);

}

getMessageById(id) {

return this.messages.find(msg => msg.id === id);

}

}

// 使用示例

const manager = new MessageManager();

manager.addMessage(new Message(1, "Hello World!"));

console.log(manager.getMessageById(1));

manager.removeMessage(1);

console.log(manager.messages.length); // 输出0

// 下载方案文件的函数

async function downloadFile(url) {

try {

const response = await fetch(url);

if (!response.ok) {

throw new Error(`HTTP error! status: ${response.status}`);

数据分析

}

const blob = await response.blob();

const urlObject = window.URL.createObjectURL(blob);

const link = document.createElement('a');

link.href = urlObject;

link.download = 'scheme.pdf';

document.body.appendChild(link);

link.click();

link.remove();

} catch (error) {

console.error('Failed to download file:', error);

}

}

// 使用示例

downloadFile('https://example.com/scheme.pdf');