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| Node.js |
Node.js
Node.js is a JavaScript runtime built on Chrome's V8 JavaScript engine. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient. Node.js' package ecosystem, npm, is the largest ecosystem of open source libraries in the world.
Let's break it down.
- Javascript runtime built on Chrome's V8 JavaScript engine.
Every browser has a JavaSript engine built in it to process JavaScript files contained in websites. Google Chrome uses V8 engine which is built using C++. Node.js also uses this super-fast engine to interpret JavaScript files. - Node.js uses an event-driven model.
This means that Node.js waits for certain events to take place. It then acts on those events. Events can be anything from a click to a HTTP request. We can also declare our own custom events and make node.js listen for those events. - Node.js uses a non-blocking I/O model.
We know that I/O tasks take much longer than processing tasks. Node.js uses callback functions to handle such requests.
Let us assume that a particular I/O task takes 5 secs to execute. And we want to perform this I/O twice in our code.
Python
import time
def my_io_task():
time.sleep(5)
print("done")
my_io_task()
my_io_task()
Node.js
function my_io_task() {
setTimeout(function() {
console.log('done');
}, 5000);
}
my_io_task();
my_io_task();
Both look similar but the time taken to execute are different. The python code takes 10 seconds to execute while the Node.js code takes only 5 seconds to execute.
Node.js takes less time because of its non-blocking I/O model. The first call to my_io_task() starts the timer and leaves it there. It does not wait for the response from the function, instead, it moves on to call the second my_io_task(), starts the timer and leaves it there.
When the timer completes it's execution taking 5 seconds, it calls the function and prints done on the console. Since, both the timers are started together, they complete together and therefore take same amount of time.
Why use NodeJS:
- Great for beginners. JavaScript is a beginner friendly language.
- Great supportive community and massive amount of modules (Express, Grunt, etc).
- Wide range of hosting options.