Question

我有一个book.js和server.js文件。我运行node ./server.js，服务器开始运行。我打开谷歌浏览器并打开开发者控制台，并输入book.rate（10），我的发射不会发生在任何地方。也许我不理解eventemitters。错误是“Uncaught Reference error: book is not defined”

Server.js

var http = require('http');
var BookClass = require('./book.js');

http.createServer(function (req, res) {
   res.writeHead(200, {'Content-Type': 'text/plain'});
   res.end('Hello World\n');
var book = new BookClass();
book.on('rated', function() {
 console.log('rated '  + book.getPoints());
}); 
}).listen(9000, '127.0.0.1');
console.log('Server running at http://127.0.0.1:9000/');

Book.js

var util = require("util");
var events = require("events");
var Class = function() { };
util.inherits(Class, events.EventEmitter);
Class.prototype.ratePoints = 0;
Class.prototype.rate = function(points) {
   ratePoints = points;
   this.emit('rated');
};
Class.prototype.getPoints = function() {
   return ratePoints;
}
module.exports = Class;

Answer 1

您获得book is not defined，因为您尚未在客户端定义book，您只在服务器端定义了它。

如果没有某种额外的库/代码来提供这种功能，你无法从浏览器中神奇地访问服务器端变量。

节点EventEmitter未给出预期结果

1 个答案: