callback example node js

package can be installed locally or globally. The differences between the two are as follows: 1) Local installation of npm install 2) Global installation of npm install-g 4.3.2 NPM package management The following uses grunt-cli (grunt command line tool) as an example to list common package management commands: 1). npm install: install all packages declared by the dependencies and devDependencies fields in the package. json File2). npm install grunt

This article focuses on. two key concepts of js: non-blocking IO and event loops are summarized appropriately. If you need them, you can refer to the following concepts to learn and use Node. javascript has been writing a web application and a RESTful web api using express and mongoose for two months. js official website homepage for

has features such as non-blocking, event-driven I/O, which makes it possible to use highly concurrent (high concurrency) polling (Polling) and comet-built applications. When you read these explanations and feel that you still don't understand them, here's a simple and rude way to help you understand your understanding of node. js. The browser's request to the website has not changed much. When the browser

stats }); Classification of one heap memory Zone var hd = new memwatch.HeapDiff(); // your code here ... var diff = hd.end(); In addition, it is useful in testing and can trigger the Garbage Collector function. Okay, there are four points in total. var stats = memwatch.gc(); Memwatch. on ('stats',...): Post-GC heap statistics Node-memwatch can produce a memory usage sample immediately after a complete garbage collection and memory compression b

this way, only the asynchronous callback can be written into an advantage immediately. The most deadly shortcomings of node. js are packaged into advantages, and no moral integrity to motivate a group of people to engage in meaningless benchmark, immediately avoiding the unfavorable situation. Shouting slogans is always the easiest, event-driven is high performa

Transmitter var memwatch = require('memwatch'); memwatch.on('stats', function(stats) { // do something with post-gc memory usage stats }); Classification of one heap memory Zone var hd = new memwatch.HeapDiff(); // your code here ... var diff = hd.end(); In addition, it is useful in testing and can trigger the Garbage Collector function. Okay, there are four points in total. var stats = memwatch.gc(); Memwatch. on ('stats',...): Post-GC heap statistics

transmitter var memwatch = require('memwatch'); memwatch.on('stats', function(stats) { // do something with post-gc memory usage stats }); Classification of one heap memory zone var hd = new memwatch.HeapDiff(); // your code here ... var diff = hd.end(); In addition, it is useful in testing and can trigger the garbage collector function. Okay, there are four points in total. var stats = memwatch.gc(); Memwatch. on ('stats',...): Post-GC heap statistics

,Then install it via the command line NPM install ****** or NPM install ******--save-devRepresents a module that needs to be installed--save-dev is the Devdependencies property that writes the installation package information to the Package.json file.After local installation, modules in the Node_modules directory in the project can be introduced via require (). As the following example, the local installation is require (' MySQL ') directly in Gulpfil

\ javascript \ nodejs-node-mysql> node app-pooling.jsWed Sep 11 2013 15:32:25 GMT + 0800 (China Standard Time) [{Variable_name: 'Wait _ timeout', Value: '10'}] Wed Sep 11 2013 15:32:30 GMT + 0800 (China Standard Time) [{Variable_name: 'Wait _ timeout', Value: '10'}] Wed Sep 11 2013 15:32:35 GMT + 0800 (China Standard Time) [{Variable_name: 'Wait _ timeout', Value: '10'}] The connection pool has solved the

Node. js Study Notes (2)-modularization, node. js Study Notes Welcome to reprint, but please indicate the source: http://blog.csdn.net/sysuzjz/article/details/43987289 Thanks: nodebeginner.org An application consists of different modules. Now we will introduce these modules one by one.In the previous section of the ser

the browser, replace the placeholder span element with jQuery's replaceWith method. The code in this article is in the https://github.com/undozen/bigpipe-on-node, I made every step into a commit, I hope you clone to the local actually run and have a look at hack. Because the loading sequence is involved in the next steps, you must open your browser to experience it and cannot see it from the top (in fact, you can use gif animation, but I am too lazy

completed the setup, but you don't know if it can run correctly, let's write an example file to test it. Create example. js in the C: cygwin directory Input Var http = require ('http '); Http. createServer (function (request, response ){ Response. writeHead (200, {'content-type': 'text/html '}); Response. end ('Hello World'); }). Listen (8888 ); Console. log ('s

feature is at the core of Node success. The following example shows how JavaScript closures work in a Web browser. If you want to listen to a single-host event of a button, you can do this: The Code is as follows: Var clickCount = 0; Document. getElementById ('myclick'). onclick = function (){ ClickCount + = 1; Alert ("clicked" + clickCount + "times ."); }; This is the case when using jQuery: The Code

chapter, the grandmother finds out his conscience and writes a callback function again.By convention, we should first write the framework: The Code is as follows:# Include Using namespace v8; Handle RunCallback (const Arguments args) { HandleScope scope; //...Return scope. Close (Undefined ());}Then we decided on its usage as follows:Func (function (msg ){Console. log (msg );});That is, it will input a parameter to the

Asynchronous programming practices of when. js under node. js, node. jswhen. js Assume a business scenario: Get and save the rss feed to a file through the rss address, and save the rss address to the file. To complete the business in this scenario, you need to complete thre

errors: Exception capture in Node. js callback Functions Node. js has many asynchronous APIs, which are processed by the callback function callback. If an error occurscallbackThe first

with global module ): Copy codeThe Code is as follows:Npm install supervisor-g Assume that the main portal of your Node. js program is app. js, you only need to execute the following command to start monitoring file changes. Copy codeThe Code is as follows:Supervisor app. js The Supervisor also supports multiple param

This article mainly introduces the asynchronous programming practices of when. js under node. js. If you need it, you can refer to the following assumptions for a business scenario: Get and save the rss feed to a file through the rss address, and save the rss address to the file. To complete the business in this scenario, you need to complete three tasks: 1. Rea

path. Node. js Website: http://nodejs.org/ Enter the tar xf node-v0.4.7.tar.gz in the Command window, node-v0.4.7.tar.gz for your own version. Enter the cd node-v0.4.7 in the Command window and press Enter. Enter./configure in the Command window and press Enter. Enter make

-v" to view the version of the Node package management tool you have installed. have you finished it? OK. Let's get started !! Open the Notepad program and we will build our first Node. js applications. copy the following code to the Notepad program and use any file name, for example, "