#4: Node.js REPL Life Cycle Explained in Hindi with Practical Examples

Hello what's up guys today in this video we will see rail in nut j yes guys I would like to tell you that our world best nut j series has started we had recently completed react version 19 so now we are starting this nut version now If you have n't checked it out till now, then definitely check out the previous video. And today we are going to see Rail, whose full form is Read Equal Print Loop. Okay, so what is this, let me tell you. Look guy, remember when we installed our node version yesterday, one thing I told you there was that let's you come to the terminal, okay you come to the terminal or you come to the power cell here, that's it now. What you have to do is to write node and if you write fun v then first of all make sure that this node is installed in your system. Make sure that the node gets installed. In yesterday's video, I told you two ways to you can do whatever you want Okay, after that if you write clear then it becomes clear. Now here you only have to write one thing that is node and you don't have to do anything else just write node and then you have to hit enter then everything is clear. You can see that you have got a prompt where it is saying welcome to nut dot jas version this type help for more information is ok dot help it is saying this if I write this in this manner then I don't have to All this is coming and then you can see here at the end I can see an angle bracket. This means that now you are inside the evolution of the nut. Yes guys, when you go to the terminal and write a note in this manner. If you hit enter then you will come inside the terminal of node JS. Basically it's your entry right now. Now let's pause it here for a while. Now let's understand that when I wrote the note. In what environment have I come, is it like a dark one, is this some awesome future of Netflix's, now I will tell you, listen carefully, we have read this in full form, right now, here he has written one thing very clearly, read it carefully. It's an interactive programming environment that allows you to execute JavaScript code one statement at a time. Yes guys, what do you understand the moment you write a note and hit enter? It means the environment that you are getting, we call it Rapal, yes guys, so this is the part that you are seeing now in the terminal, I see it, Control and then C and Control and then C or Control D also you. If you can press control twice, I am clearing it again. The moment whenever you write a note in your terminal, power cell, wherever you are, earn promotion, you do it in Visual Studio code also, wherever you go, just write the note. If you hit enter, then after that you get the item where you can go to the script and write the code one at a time, then that is called your rail, this evolution that you have got, now it is called your rail. That's it, we are a repeater, I will tell you, now here you see 2 + 2, your output has come 3 * 3, see your 9 has come, okay, if you want to use modus operator, you can do that, but this modus No, this is your division, here you can also write the code, for now, I do one thing here, look carefully, let's construct array, I do one thing here, I am making an array, okay. Look, I am there, so the note is inside it is fine, in this way I created an array, I will hit enter, so now if I write AR, I am getting an array, now in this array, I show the map using map method. is n't it like this From this I use a map where there is nothing, I write ' Naam' or 'Naam', then one by one I will get this 'Naam * 3' and I hit 'Enter', then look, I am getting data here in this way, so to say This means that whenever you go to any terminal and write node there and hit enter, you will get an environment where you can type JavaScript code, then this development is called your rail. Now here is one thing. These Okay, there are more things here, look, I told you that you can use it to test simple JavaScript codes. You can write simple JavaScript codes here instead of going to the browser and console, you can do this from end control. You can exit, now this is the most important and I think you will not get this in many courses and that's it guys, this is Rail, the first thing in this is your read, then comes your read, then comes your print. And then comes your loop, so what is happening here, I will tell you, look carefully, okay, then I will clear it once and see, it is okay here, it is not getting cleared, remove it, I will clear it here now. Let me show it well, suppose I write 2 + 2. Okay, what am I going to do, I am writing 2 + 2 and I am going to hit enter. I got the answer four, so your rappel is hidden in it, carefully. Listen to the moment you write 2 + 2 it means, now look carefully at this wraparound, this particular code, whatever code you wrote in the script, what did it do with it, read it, what did it read and pass it into where the data is. Structure that the JavaScript engine can understand, guys, what did he do, he passed it to the read key and data structure so that the JavaScript engine can understand that brother, what is written, right after that, it is evaluable at now when read. That data is passed to the JavaScript engine, then what will the JavaScript engine do? It will evaluate the particular thing. After all, what does the user want? Well, 2+2 means if he wants addition, then that evaluation has been written for him. It is valid or not, if it is valid then it will give the output, basically it will pass and after that whatever output is passed, it gets printed and the same data is visible to you on your console, so I have its information here. The data appeared is four and after that, now the same three process will continue on the loop, again if you write 4 + 4 then in the loop it is ready, read it is ok 4 + 4, now it will read the loop read. After doing this, it will pass it to the JavaScript engine, the JavaScript engine will evaluate it, see if this expression is valid, then what it will do with its output, it will print it and then it will run on the loop again, so guys, this is Is your ripple, where is this thing that you are feeling, then child 2+ 2 but in behind the scene, first this is your raid, then after passing it, it is passed to the Jas cut engine, is its evaluation valid or not? If it is valid, then you get output on your console and then loop again. Ready to continue when someone gives some expression, I read it and evaluate it. If I print the data, in this way it is called your rappel, this entire environment where you are able to write the code of JavaScript, this is your Rails and the full form of Rails means this, so I hope that today in this video Now finally, this was your doubt, papal, that you will never forget the meaning of Rail in actual, till now no one has even told this, everyone says this, write node and hit enter, you are in Rail, where But you can write code in JavaScript. But I hope finally now you know that you can write code in Rails. That's it. Now in tomorrow's video I will tell you what is CL and can you use Rails there. I can also I ca n't I can't but for that you will have to wait and guys I want if you see press control D you will come out in one go so guys how did you like the video let me know in the Comment section and nut As this series is very important, React version 19 has been recently finished, please check it out and I would like to tell you that guys, I told you in a pre-requirement that whatever happens, you need to know JavaScript, especially your one script, please, this is mine. This is the world best JavaScript course, definitely watch it. Share it with your friends because guys, I have created 28 hours of JavaScript. Do you understand that the like views are very less and the content I have created. I have posted it here, if you see it once then I will write it and give you that content. If you don't find big institutes, I will give you that content by writing it. Watch it once. I will be very happy. And how did you like today's video? And finally, what was there was, I hope. That whole doubt got cleared and in life you are not going to say that what was this after all and why was it called like this, it is okay to say it so guys I will meet you in tomorrow's video but before that if you liked the video then please like. Please do share with your friends as much as you can and our next target is 7 lakh subscribers and very close guys please subscribe, a red bell icon will also appear on the right side, hit that too so that the daily notification at 4:00 pm I will upload the video, don't miss it and many more awesome videos are yet to come. Ok guys, I will meet you in tomorrow's video till then guys. Thank you so much. Care [Music]