nodejs-server

问题 I'm the author of a Node.js library and I want to use Async Hooks to improve DX. But I'm worried about performance. I've read stories saying that everything is fine, as well as stories where performance was a blocker. In theory, asynchronicity should only happen for IO operations and performance penality should be pretty much ~0. (As IO operations are several orders of magnitude more expensive than running JS code.) But, in practice, does running extra JS on each async call induces a non

问题 I'm the author of a Node.js library and I want to use Async Hooks to improve DX. But I'm worried about performance. I've read stories saying that everything is fine, as well as stories where performance was a blocker. In theory, asynchronicity should only happen for IO operations and performance penality should be pretty much ~0. (As IO operations are several orders of magnitude more expensive than running JS code.) But, in practice, does running extra JS on each async call induces a non

问题 I'm the author of a Node.js library and I want to use Async Hooks to improve DX. But I'm worried about performance. I've read stories saying that everything is fine, as well as stories where performance was a blocker. In theory, asynchronicity should only happen for IO operations and performance penality should be pretty much ~0. (As IO operations are several orders of magnitude more expensive than running JS code.) But, in practice, does running extra JS on each async call induces a non

问题 I'm the author of a Node.js library and I want to use Async Hooks to improve DX. But I'm worried about performance. I've read stories saying that everything is fine, as well as stories where performance was a blocker. In theory, asynchronicity should only happen for IO operations and performance penality should be pretty much ~0. (As IO operations are several orders of magnitude more expensive than running JS code.) But, in practice, does running extra JS on each async call induces a non

问题 I’m working on a stateful and websocket server on Node. We require a piece of read-only data that is important for the biz logic and save it in Node’s global scope, and recently we have to invalidate this require cache and re-require to allow changes of this piece of data at runtime. My question is should we worry simply reassigning the global variable the result of the re-require would cause issues between concurrent connections which read this single copy of data at different phases? Thanks

问题 This is my file loginHandler.js class LoginHandler { merchantId = ''; returnURLForIframe(req, res) { merchantId = req.params.merchantId; } } module.exports = new LoginHandler(); I want to access the variable merchantId on another file const loginHandler = require('./loginHandler') class ResponseHandler { getResponseFromCOMM(options,token, res){ console.log(loginHandler.merchantId) } } But merchantId is undefined. Can you please tell me what I am doing wrong? Here you can see the code on

来源： https://stackoverflow.com/questions/56821291/nodejs-environment-variables-undefined

问题 I have 2 files in Node js .I want to merge these 2, but I am facing problem.. This file calls function from python file const app = express() let runPy = new Promise(function(success, nosuccess) { const { spawn } = require('child_process'); const pyprog = spawn('python', ['./ml.py']); pyprog.stdout.on('data', function(data) { success(data); }); pyprog.stderr.on('data', (data) => { nosuccess(data); }); }); app.get('/', (req, res) => { res.write('welcome\n'); runPy.then(function(testMLFunction)

问题 I tried crud Operation using node js and mongodb.all crud operation working fine.but i tried to run get method its showing on;y one record.after i see my code its throwing error (Can't set headers after they are sent).How to solve this issue any one give suggestion. index.js router.get('/', async (req, res,next) => { (async function() { try { await client.connect(); console.log("Connected correctly to server"); const db = client.db('olc_prod_db'); let r = await db.collection('Ecommerce').find

问题 I want to process array of length around 100 000, without putting too much load on CPU. I researched about streams and stumbled upon highlandjs, but i am unable to make it work. I also tried using promises and processing in chunks but still it is putting very much load on CPU, program can be slow if needed but should not put load on CPU 回答1: With node.js which runs your Javascript as single threaded, if you want your server to be maximally responsive to incoming requests, then you need to