1597433040
Node.js es un entorno de tiempo de ejecución de código abierto basado en JavaScript que use usa para crear aplicaciones de redes. La plataforma funciona en Linux, macOS, FreeBSD y Windows. Aunque puede ejecutar aplicaciones de Node.js en la línea de comandos, en este tutorial se pondrá el foco en su ejecución como un servicio. Esto significa que se reiniciarán durante el inicio o ante un fallo y que pueden usarse de forma segura en un entorno de producción.
En este tutorial, configurará un entorno de Node.js listo para producción en un servidor único Ubuntu 20.04. Este servidor ejecutará una aplicación de Node.js administrada por PM2 y brindará a los usuarios acceso seguro a la aplicación mediante un proxy inverso de Nginx. El servidor de Nginx brindará HTTPS usando un certificado gratuito proporcionado por Let’s Encrypt.
Para esta guía, se supone cuenta con lo siguiente:
Una vez que cumpla con los requisitos previos, dispondrá de un servidor en el que funcionará la página de marcador de posición predeterminada de su dominio en https://``example.com``/
.
Comencemos instalando la versión más reciente de LTS de Node.js con los archivos de paquete de NodeSource.
Primero, instale el PPA de NodeSource para poder acceder a su contenido. Asegúrese de estar en su directorio de inicio y utilice curl
para recuperar la secuencia de comandos de instalación para la versión más reciente LTS de Node.js de sus archivos.
cd ~
curl -sL https://deb.nodesource.com/setup_14.x -o nodesource_setup.sh
Puede inspeccionar el contenido de esta secuencia de comandos con nano
o su editor de texto preferido:
nano nodesource_setup.sh
Cuando termine de inspeccionar la secuencia, ejecútela con sudo
:
sudo bash nodesource_setup.sh
El PPA se agregará a su configuración y su caché de paquetes locales se actualizará de forma automática. Después de ejecutar la secuencia de comandos de configuración de Nodesource, puede instalar el paquete de Node.js.
sudo apt install nodejs
Para comprobar la versión de Node.js que instaló después de estos pasos iniciales, escriba lo siguiente:
nodejs -v
Output
v14.4.0
Nota: Cuando la instalación se realiza a partir del PPA de NodeSource, el ejecutable de Node.js se llama nodejs
, en lugar de node
.
El paquete nodejs
contiene el binario nodejs
y [npm](https://www.npmjs.com/)
un administrador de paquetes para módulos de Node, por lo que no tendrá que instalar npm
por separado.
npm
utiliza un archivo de configuración en su directorio de inicio para hacer un seguimiento de las actualizaciones. Se creará la primera vez que ejecute npm
. Ejecute este comando para verificar que npm
esté instalado y crear el archivo de configuración:
npm -v
Output
6.14.5
Para que algunos paquetes de npm
funcionen (por ejemplo, aquellos para los cuales de sebe compilar código de fuente), deberá instalar el paquete build-essential
:
sudo apt install build-essential
Ahora dispondrá de las herramientas necesarias para trabajar con paquetes npm
para los que se deba compilar código de la fuente.
Ahora que está instalado el tiempo de ejecución de Node.js, escribiremos una la aplicación de Node.js.
#ubuntu
1632537859
Not babashka. Node.js babashka!?
Ad-hoc CLJS scripting on Node.js.
Experimental. Please report issues here.
Nbb's main goal is to make it easy to get started with ad hoc CLJS scripting on Node.js.
Additional goals and features are:
Nbb requires Node.js v12 or newer.
CLJS code is evaluated through SCI, the same interpreter that powers babashka. Because SCI works with advanced compilation, the bundle size, especially when combined with other dependencies, is smaller than what you get with self-hosted CLJS. That makes startup faster. The trade-off is that execution is less performant and that only a subset of CLJS is available (e.g. no deftype, yet).
Install nbb
from NPM:
$ npm install nbb -g
Omit -g
for a local install.
Try out an expression:
$ nbb -e '(+ 1 2 3)'
6
And then install some other NPM libraries to use in the script. E.g.:
$ npm install csv-parse shelljs zx
Create a script which uses the NPM libraries:
(ns script
(:require ["csv-parse/lib/sync$default" :as csv-parse]
["fs" :as fs]
["path" :as path]
["shelljs$default" :as sh]
["term-size$default" :as term-size]
["zx$default" :as zx]
["zx$fs" :as zxfs]
[nbb.core :refer [*file*]]))
(prn (path/resolve "."))
(prn (term-size))
(println (count (str (fs/readFileSync *file*))))
(prn (sh/ls "."))
(prn (csv-parse "foo,bar"))
(prn (zxfs/existsSync *file*))
(zx/$ #js ["ls"])
Call the script:
$ nbb script.cljs
"/private/tmp/test-script"
#js {:columns 216, :rows 47}
510
#js ["node_modules" "package-lock.json" "package.json" "script.cljs"]
#js [#js ["foo" "bar"]]
true
$ ls
node_modules
package-lock.json
package.json
script.cljs
Nbb has first class support for macros: you can define them right inside your .cljs
file, like you are used to from JVM Clojure. Consider the plet
macro to make working with promises more palatable:
(defmacro plet
[bindings & body]
(let [binding-pairs (reverse (partition 2 bindings))
body (cons 'do body)]
(reduce (fn [body [sym expr]]
(let [expr (list '.resolve 'js/Promise expr)]
(list '.then expr (list 'clojure.core/fn (vector sym)
body))))
body
binding-pairs)))
Using this macro we can look async code more like sync code. Consider this puppeteer example:
(-> (.launch puppeteer)
(.then (fn [browser]
(-> (.newPage browser)
(.then (fn [page]
(-> (.goto page "https://clojure.org")
(.then #(.screenshot page #js{:path "screenshot.png"}))
(.catch #(js/console.log %))
(.then #(.close browser)))))))))
Using plet
this becomes:
(plet [browser (.launch puppeteer)
page (.newPage browser)
_ (.goto page "https://clojure.org")
_ (-> (.screenshot page #js{:path "screenshot.png"})
(.catch #(js/console.log %)))]
(.close browser))
See the puppeteer example for the full code.
Since v0.0.36, nbb includes promesa which is a library to deal with promises. The above plet
macro is similar to promesa.core/let
.
$ time nbb -e '(+ 1 2 3)'
6
nbb -e '(+ 1 2 3)' 0.17s user 0.02s system 109% cpu 0.168 total
The baseline startup time for a script is about 170ms seconds on my laptop. When invoked via npx
this adds another 300ms or so, so for faster startup, either use a globally installed nbb
or use $(npm bin)/nbb script.cljs
to bypass npx
.
Nbb does not depend on any NPM dependencies. All NPM libraries loaded by a script are resolved relative to that script. When using the Reagent module, React is resolved in the same way as any other NPM library.
To load .cljs
files from local paths or dependencies, you can use the --classpath
argument. The current dir is added to the classpath automatically. So if there is a file foo/bar.cljs
relative to your current dir, then you can load it via (:require [foo.bar :as fb])
. Note that nbb
uses the same naming conventions for namespaces and directories as other Clojure tools: foo-bar
in the namespace name becomes foo_bar
in the directory name.
To load dependencies from the Clojure ecosystem, you can use the Clojure CLI or babashka to download them and produce a classpath:
$ classpath="$(clojure -A:nbb -Spath -Sdeps '{:aliases {:nbb {:replace-deps {com.github.seancorfield/honeysql {:git/tag "v2.0.0-rc5" :git/sha "01c3a55"}}}}}')"
and then feed it to the --classpath
argument:
$ nbb --classpath "$classpath" -e "(require '[honey.sql :as sql]) (sql/format {:select :foo :from :bar :where [:= :baz 2]})"
["SELECT foo FROM bar WHERE baz = ?" 2]
Currently nbb
only reads from directories, not jar files, so you are encouraged to use git libs. Support for .jar
files will be added later.
The name of the file that is currently being executed is available via nbb.core/*file*
or on the metadata of vars:
(ns foo
(:require [nbb.core :refer [*file*]]))
(prn *file*) ;; "/private/tmp/foo.cljs"
(defn f [])
(prn (:file (meta #'f))) ;; "/private/tmp/foo.cljs"
Nbb includes reagent.core
which will be lazily loaded when required. You can use this together with ink to create a TUI application:
$ npm install ink
ink-demo.cljs
:
(ns ink-demo
(:require ["ink" :refer [render Text]]
[reagent.core :as r]))
(defonce state (r/atom 0))
(doseq [n (range 1 11)]
(js/setTimeout #(swap! state inc) (* n 500)))
(defn hello []
[:> Text {:color "green"} "Hello, world! " @state])
(render (r/as-element [hello]))
Working with callbacks and promises can become tedious. Since nbb v0.0.36 the promesa.core
namespace is included with the let
and do!
macros. An example:
(ns prom
(:require [promesa.core :as p]))
(defn sleep [ms]
(js/Promise.
(fn [resolve _]
(js/setTimeout resolve ms))))
(defn do-stuff
[]
(p/do!
(println "Doing stuff which takes a while")
(sleep 1000)
1))
(p/let [a (do-stuff)
b (inc a)
c (do-stuff)
d (+ b c)]
(prn d))
$ nbb prom.cljs
Doing stuff which takes a while
Doing stuff which takes a while
3
Also see API docs.
Since nbb v0.0.75 applied-science/js-interop is available:
(ns example
(:require [applied-science.js-interop :as j]))
(def o (j/lit {:a 1 :b 2 :c {:d 1}}))
(prn (j/select-keys o [:a :b])) ;; #js {:a 1, :b 2}
(prn (j/get-in o [:c :d])) ;; 1
Most of this library is supported in nbb, except the following:
:syms
.-x
notation. In nbb, you must use keywords.See the example of what is currently supported.
See the examples directory for small examples.
Also check out these projects built with nbb:
See API documentation.
See this gist on how to convert an nbb script or project to shadow-cljs.
Prequisites:
To build:
bb release
Run bb tasks
for more project-related tasks.
Download Details:
Author: borkdude
Download Link: Download The Source Code
Official Website: https://github.com/borkdude/nbb
License: EPL-1.0
#node #javascript
1616671994
If you look at the backend technology used by today’s most popular apps there is one thing you would find common among them and that is the use of NodeJS Framework. Yes, the NodeJS framework is that effective and successful.
If you wish to have a strong backend for efficient app performance then have NodeJS at the backend.
WebClues Infotech offers different levels of experienced and expert professionals for your app development needs. So hire a dedicated NodeJS developer from WebClues Infotech with your experience requirement and expertise.
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For inquiry click here: https://www.webcluesinfotech.com/hire-nodejs-developer/
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1622719015
Front-end web development has been overwhelmed by JavaScript highlights for quite a long time. Google, Facebook, Wikipedia, and most of all online pages use JS for customer side activities. As of late, it additionally made a shift to cross-platform mobile development as a main technology in React Native, Nativescript, Apache Cordova, and other crossover devices.
Throughout the most recent couple of years, Node.js moved to backend development as well. Designers need to utilize a similar tech stack for the whole web project without learning another language for server-side development. Node.js is a device that adjusts JS usefulness and syntax to the backend.
Node.js isn’t a language, or library, or system. It’s a runtime situation: commonly JavaScript needs a program to work, however Node.js makes appropriate settings for JS to run outside of the program. It’s based on a JavaScript V8 motor that can run in Chrome, different programs, or independently.
The extent of V8 is to change JS program situated code into machine code — so JS turns into a broadly useful language and can be perceived by servers. This is one of the advantages of utilizing Node.js in web application development: it expands the usefulness of JavaScript, permitting designers to coordinate the language with APIs, different languages, and outside libraries.
Of late, organizations have been effectively changing from their backend tech stacks to Node.js. LinkedIn picked Node.js over Ruby on Rails since it took care of expanding responsibility better and decreased the quantity of servers by multiple times. PayPal and Netflix did something comparative, just they had a goal to change their design to microservices. We should investigate the motivations to pick Node.JS for web application development and when we are planning to hire node js developers.
The principal thing that makes Node.js a go-to environment for web development is its JavaScript legacy. It’s the most well known language right now with a great many free devices and a functioning local area. Node.js, because of its association with JS, immediately rose in ubiquity — presently it has in excess of 368 million downloads and a great many free tools in the bundle module.
Alongside prevalence, Node.js additionally acquired the fundamental JS benefits:
In addition, it’s a piece of a well known MEAN tech stack (the blend of MongoDB, Express.js, Angular, and Node.js — four tools that handle all vital parts of web application development).
This is perhaps the most clear advantage of Node.js web application development. JavaScript is an unquestionable requirement for web development. Regardless of whether you construct a multi-page or single-page application, you need to know JS well. On the off chance that you are now OK with JavaScript, learning Node.js won’t be an issue. Grammar, fundamental usefulness, primary standards — every one of these things are comparable.
In the event that you have JS designers in your group, it will be simpler for them to learn JS-based Node than a totally new dialect. What’s more, the front-end and back-end codebase will be basically the same, simple to peruse, and keep up — in light of the fact that they are both JS-based.
There’s another motivation behind why Node.js got famous so rapidly. The environment suits well the idea of microservice development (spilling stone monument usefulness into handfuls or many more modest administrations).
Microservices need to speak with one another rapidly — and Node.js is probably the quickest device in information handling. Among the fundamental Node.js benefits for programming development are its non-obstructing algorithms.
Node.js measures a few demands all at once without trusting that the first will be concluded. Many microservices can send messages to one another, and they will be gotten and addressed all the while.
Node.js was worked in view of adaptability — its name really says it. The environment permits numerous hubs to run all the while and speak with one another. Here’s the reason Node.js adaptability is better than other web backend development arrangements.
Node.js has a module that is liable for load adjusting for each running CPU center. This is one of numerous Node.js module benefits: you can run various hubs all at once, and the environment will naturally adjust the responsibility.
Node.js permits even apportioning: you can part your application into various situations. You show various forms of the application to different clients, in light of their age, interests, area, language, and so on. This builds personalization and diminishes responsibility. Hub accomplishes this with kid measures — tasks that rapidly speak with one another and share a similar root.
What’s more, Node’s non-hindering solicitation handling framework adds to fast, letting applications measure a great many solicitations.
Numerous designers consider nonconcurrent to be one of the two impediments and benefits of Node.js web application development. In Node, at whatever point the capacity is executed, the code consequently sends a callback. As the quantity of capacities develops, so does the number of callbacks — and you end up in a circumstance known as the callback damnation.
In any case, Node.js offers an exit plan. You can utilize systems that will plan capacities and sort through callbacks. Systems will associate comparable capacities consequently — so you can track down an essential component via search or in an envelope. At that point, there’s no compelling reason to look through callbacks.
So, these are some of the top benefits of Nodejs in web application development. This is how Nodejs is contributing a lot to the field of web application development.
I hope now you are totally aware of the whole process of how Nodejs is really important for your web project. If you are looking to hire a node js development company in India then I would suggest that you take a little consultancy too whenever you call.
Good Luck!
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1616839211
Top organizations and start-ups hire Node.js developers from SISGAIN for their strategic software development projects in Illinois, USA. On the off chance that you are searching for a first rate innovation to assemble a constant Node.js web application development or a module, Node.js applications are the most appropriate alternative to pick. As Leading Node.js development company, we leverage our profound information on its segments and convey solutions that bring noteworthy business results. For more information email us at hello@sisgain.com
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1597433040
Node.js es un entorno de tiempo de ejecución de código abierto basado en JavaScript que use usa para crear aplicaciones de redes. La plataforma funciona en Linux, macOS, FreeBSD y Windows. Aunque puede ejecutar aplicaciones de Node.js en la línea de comandos, en este tutorial se pondrá el foco en su ejecución como un servicio. Esto significa que se reiniciarán durante el inicio o ante un fallo y que pueden usarse de forma segura en un entorno de producción.
En este tutorial, configurará un entorno de Node.js listo para producción en un servidor único Ubuntu 20.04. Este servidor ejecutará una aplicación de Node.js administrada por PM2 y brindará a los usuarios acceso seguro a la aplicación mediante un proxy inverso de Nginx. El servidor de Nginx brindará HTTPS usando un certificado gratuito proporcionado por Let’s Encrypt.
Para esta guía, se supone cuenta con lo siguiente:
Una vez que cumpla con los requisitos previos, dispondrá de un servidor en el que funcionará la página de marcador de posición predeterminada de su dominio en https://``example.com``/
.
Comencemos instalando la versión más reciente de LTS de Node.js con los archivos de paquete de NodeSource.
Primero, instale el PPA de NodeSource para poder acceder a su contenido. Asegúrese de estar en su directorio de inicio y utilice curl
para recuperar la secuencia de comandos de instalación para la versión más reciente LTS de Node.js de sus archivos.
cd ~
curl -sL https://deb.nodesource.com/setup_14.x -o nodesource_setup.sh
Puede inspeccionar el contenido de esta secuencia de comandos con nano
o su editor de texto preferido:
nano nodesource_setup.sh
Cuando termine de inspeccionar la secuencia, ejecútela con sudo
:
sudo bash nodesource_setup.sh
El PPA se agregará a su configuración y su caché de paquetes locales se actualizará de forma automática. Después de ejecutar la secuencia de comandos de configuración de Nodesource, puede instalar el paquete de Node.js.
sudo apt install nodejs
Para comprobar la versión de Node.js que instaló después de estos pasos iniciales, escriba lo siguiente:
nodejs -v
Output
v14.4.0
Nota: Cuando la instalación se realiza a partir del PPA de NodeSource, el ejecutable de Node.js se llama nodejs
, en lugar de node
.
El paquete nodejs
contiene el binario nodejs
y [npm](https://www.npmjs.com/)
un administrador de paquetes para módulos de Node, por lo que no tendrá que instalar npm
por separado.
npm
utiliza un archivo de configuración en su directorio de inicio para hacer un seguimiento de las actualizaciones. Se creará la primera vez que ejecute npm
. Ejecute este comando para verificar que npm
esté instalado y crear el archivo de configuración:
npm -v
Output
6.14.5
Para que algunos paquetes de npm
funcionen (por ejemplo, aquellos para los cuales de sebe compilar código de fuente), deberá instalar el paquete build-essential
:
sudo apt install build-essential
Ahora dispondrá de las herramientas necesarias para trabajar con paquetes npm
para los que se deba compilar código de la fuente.
Ahora que está instalado el tiempo de ejecución de Node.js, escribiremos una la aplicación de Node.js.
#ubuntu