问题描述
我有两个JavaScript文件。为简单起见,我创建了路由器,并希望维护一个变量并在所有文件中更改其值,类似于Java的静态字段。
I have two javascript files. For simplicity I have created routers and I want to maintain one variable and change its value across all files, something similar to java's static fields. but the variable I want to initialize doesn't get initialize.
就像server.js文件中一样,我有Vmessages变量,我想使其类似于Java的satic变量。因此我可以在另一个文件中更改其值,并访问server.js文件中的更改。这是server.js文件,
Like in the server.js file I have Vmessages variable I want to make it something similar to java's satic variable so I can change its value in another file and access the changes in server.js file. This is server.js file,
//server.js file
var Vmessages = [{text: 'some text', owner: 'Tim'},{text: 'other message', owner: 'Jane'}];
app.get('/messages', (req, res) => {
res.json(Vmessages);
});
module.exports.variableName = Vmessages;
app.use(require('./routes/messages'));
所以我已经导入了server.js文件的Vmessages变量,并在messages.js文件中更改了它的值。正如您在下面的代码片段中所看到的,我可以访问server.js文件的变量并进行更改。甚至在我打印时,它也表明已进行更改。但是当我访问server.js文件中的Vmessages时,它的值没有改变,而是在它的初始值中。
So I have imported the server.js files Vmessages variable and change its value in messages.js file. As you can see in the code snippet below i can access the server.js file's variable and make changes. And even when I print it it shows changes are made. But when I access the Vmessages in server.js file its value didn't change and it was in its initial value.
//messages.js file
var sourceFile = require('../server.js');
var messages = sourceFile.variableName;
router.post('/messages', (req, res) => {
console.log(sourceFile.variableName); //[{text: 'some text', owner: 'Tim'}]
messages.push({text: 'other message', owner: 'Jane'});
console.log(sourceFile.variableName); //[{text: 'some text', owner: 'Tim'},{text: 'other message', owner: 'Jane'}]
res.json(req.body);
})
module.exports = router;
这在哪里弄错了?
推荐答案
@ M.Ramzan使用此代码。我对路线代码做了一些更改。这可以按照您的要求工作。这里 server.js
文件
@M.Ramzan use this code . I made some changes to routes code. This works as per your requirement. Here server.js
file
var express = require('express');
var app = express();
var variableName;
var Vmessages = [{text: 'some text', owner: 'Tim'},{text: 'other message', owner: 'Jane'}];
app.get('/messages', (req, res) => {
res.json(Vmessages);
});
exports.variableName = Vmessages;
app.use(require('./routes/messages'));
app.listen(3000,function(){
console.log("Server listening on 3000");
});
这里是 messages.js
文件
//messages.js file
var express = require('express');
var bodyParser = require('body-parser');
var sourceFile = require('../server.js');
var app = express();
var messages = sourceFile.variableName;
var router = express.Router();
router.use(bodyParser.json());
router.post('/messages', (req, res) => {
console.log(sourceFile.variableName);
messages.push(req.body);
res.json(messages);
});
module.exports = router;
以 node server.js
的身份运行serevr 。您可以使用 get
方法以 http:// localhost:3000 / messages
的形式在Vmessages中获取数据。您可以使用 post
方法使用 http:// localhost:3000 / messages
将数据添加到Vmessages。您可以使用请求正文添加数据。希望这会有所帮助.....
Run the serevr as node server.js
. And you can get the data in Vmessages as http://localhost:3000/messages
using get
method. And you can add data to Vmessages using http://localhost:3000/messages
using post
method. You can add data by using request body. Hope this helps.....
这篇关于全局变量未获取初始化的node.js的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!