Node.js & Servers Overview

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>> Scott Moss: Anybody ever thought about what a JavaScript engine is or haven't experienced what a JavaScript engine is what that actually means? It's a compiler, right? Like it's compiling down to some C language that then compiles down to some machine code that gets read by, the computer. So each browser is built on their own version of what that engine is so V8.

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So each browser is built on their own version of what that engine is so V8. It's Chrome's, Apple has. I don't even know what Apple has anymore. I think Internet Explorer has an maybe V8 now or a WebKit.

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I think Internet Explorer has an maybe V8 now or a WebKit. I don't know. I honestly, I can't keep up anymore, but these are engines that you'll never have to interact with unless that's your job. Primary purpose of a JavaScript, in the browser is basically like do DOM stuff, do UI stuff, make HTTP calls, you know, we all know that global object is the window.

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Primary purpose of a JavaScript, in the browser is basically like do DOM stuff, do UI stuff, make HTTP calls, you know, we all know that global object is the window. We have DOM APIs, web APIs, We take this for granted, but we have free security in the browser. The browser protects us, right? I think that's the.

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I think that's the. That's the biggest job of a browser. Like, sure, a browser takes us to a website allows us to see HTML, but you can do that in your terminal. It just won't look good.

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It just won't look good. What the what the browser actually does, the main workhorse in my opinion is. The security it keeps you safe like. If the browser wasn't doing what it was doing those specs were not created, you would have been.

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If the browser wasn't doing what it was doing those specs were not created, you would have been. You would the first Chrome extension you were installed, your computer would have died. Because that's how easy it is to do stuff, so the browser sandboxes your environment then today browsers do have module systems. I'm not sure if anybody's using them or not because we all still use bundlers like Vite Webpack that do it for us, but you can natively use ES modules in the browser today in most modern browsers, which is pretty cool, but no one's ever gonna use them because like how am I ever gonna turn my JPEG into a module?

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I'm not sure if anybody's using them or not because we all still use bundlers like Vite Webpack that do it for us, but you can natively use ES modules in the browser today in most modern browsers, which is pretty cool, but no one's ever gonna use them because like how am I ever gonna turn my JPEG into a module? Yeah, you still need Vite or Webpack for that, so. These are just for JavaScript modules. Who the hell wants to go back into ordering what script tags, loading what order?

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Who the hell wants to go back into ordering what script tags, loading what order? I'm not doing that. Cool. No just JavaScript, It uses Chrome's V8 engine, so it took the same engine we Not we, but some somebody threw it on your computer operating system level, so on your terminal, so you get the same JavaScript features.

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No just JavaScript, It uses Chrome's V8 engine, so it took the same engine we Not we, but some somebody threw it on your computer operating system level, so on your terminal, so you get the same JavaScript features. Notice I said features for JavaScript not APIs, just the features for JavaScript, but in your terminal in your runtime, right? So like if you go to your terminal you have Node installed, you can just type node, right? Then now you get this REPL, which you can do JavaScript thing so everything you could have done in JavaScript, you can still do here so.

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Then now you get this REPL, which you can do JavaScript thing so everything you could have done in JavaScript, you can still do here so. No, it's the same thing. Primary purpose of Node.JS JavaScript build servers, access file systems, you know, be Edward Snowden, do stuff like that. Really cool They like the stuff that like if you told your folks, they just would not, they would think that like you were a wizard.

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Really cool They like the stuff that like if you told your folks, they just would not, they would think that like you were a wizard. This is what Node.js is for, like, this is truly what I think. Like when you start getting into like OS level OS level languages runtime environments, that's where like the power is. There's no window, but there is something called global or global this the literally the global is called global, like that's what it's called if I go here type global.

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There's no window, but there is something called global or global this the literally the global is called global, like that's what it's called if I go here type global. It's a, it's a global. That's what it's called, it's not window. APIs available, file systems, networking, process management, crypto, not crypto coins, something else, security.

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APIs available, file systems, networking, process management, crypto, not crypto coins, something else, security. G G's, you gotta roll your own, your own security. You're not gonna get no security in Node. Is that a flaw?

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Is that a flaw? Probably all the new JavaScript runtimes that are coming out like Bun or Deno, which Deno was created by the guy who made Node, have security built in very similar to the browser now where you have to like opt in, but Node nah. You figure it out. You do your own security, so this is where I was like, you're gonna realize that like you got it for free with the browser then module system historically it was CommonJS with the latest versions of Node we get ESM.

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You do your own security, so this is where I was like, you're gonna realize that like you got it for free with the browser then module system historically it was CommonJS with the latest versions of Node we get ESM. So if you're on the version that I told you to, you'll have ESM. If you don't know what ESM is what CommonJS is. I don't want, I want you to have that innocence.

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I don't want, I want you to have that innocence. I don't wanna take that from you. I don't wanna remind you what CommonJS is. Just continue on down your ESM track.

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Just continue on down your ESM track. We don't need a history lesson. So understanding servers from a front-end engineer's perspective, I think this is key, right? So like on the front-end, you'll do something like this.

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So like on the front-end, you'll do something like this. You'll fetch this API, right? Well, to handle that on the back-end you gotta, you gotta make a route for that. So this is what we're gonna be doing.

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So this is what we're gonna be doing. We're gonna make a routes. That that's where this goes. So if you only ever did front-end it was like.

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So if you only ever did front-end it was like. You have no idea what the hell is happening with this calls. There you go. That's what's happening.

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That's what's happening. That's a small part of what's happening, OK? The other thing is like this sounds obvious now I'm sorry if it's very obvious, but to me when I was learning I did not understand this concept because I was just new to computer science in general was that. For a client app this could be a website this could be a mobile app, this could be a smart TV app this could be a desktop app we all have our own version of that running on our machine our machine is powering that client that client traditionally from some central computer that we all share resources from that is a server, right?

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For a client app this could be a website this could be a mobile app, this could be a smart TV app this could be a desktop app we all have our own version of that running on our machine our machine is powering that client that client traditionally from some central computer that we all share resources from that is a server, right? So if we both are on if we're all on the same notion website right now. That website is being served to us individually on our browsers on our computers eating our resources individually. But the server that's serving this.

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But the server that's serving this. I know it's a CDN, but let's assume it's a server. All of our clients are sharing that one server, so we're all sharing the resources from that server. So that's a big difference, right?

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So that's a big difference, right? Because like right now. If this website has an error, let's say they have like a scrolling animation, when I scroll, it crashes out. Cool, I'll just refresh my page like I'm good to go or maybe actually it'll probably continue to work even though it crashed because it's not really doing anything.

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Cool, I'll just refresh my page like I'm good to go or maybe actually it'll probably continue to work even though it crashed because it's not really doing anything. If the server crashes, well nobody can use it because we all share that one server, right, in the case of like not scaling things like that. That to me, I did not understand that. So if you, if you get that already, good for you.

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So if you, if you get that already, good for you. I was not some that was not intuitive to me. It took me a while to really understand that obviously there's like architecture around like scale scaling you know, load balancing horizontal vertical scaling like all this stuff serverless, you know, but. The difference between a computer.

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The difference between a computer. You know that's a server a client that's a big difference. Types of backing services we have long-lived servers that's what we're gonna make today. I know everybody's doing serveless we're not doing serverless, I'll talk about service we're not gonna do it.

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I know everybody's doing serveless we're not doing serverless, I'll talk about service we're not gonna do it. We're doing long-lived traditional servers. This just means it's a program that's never off. You could think of like a loop that never ends.

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You could think of like a loop that never ends. If you did an infinite loop on your computer right now, don't do that. You'll eat up all your RAM you won't be able to use your computer. You can think about it like that.

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You can think about it like that. It's a, it's a process that never shuts down until you tell it to or it crashes, so that's what a traditional long the server is. Their service functions, these are like just think of like take a function. It's not active until you hit it with a with a route.

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It's not active until you hit it with a with a route. It turns on, it executes your code, then it shuts down, right? So. You can still do the same things you could traditionally do on a long-lived server, you just don't have to pay for when it's not running.

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You can still do the same things you could traditionally do on a long-lived server, you just don't have to pay for when it's not running. But you do have to trade off for like speed architecture. There's only you can't use. Long-lived things like WebSockets stuff like that in a serverless environment.

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Long-lived things like WebSockets stuff like that in a serverless environment. We have edge functions which are the same thing as serverless but on a CDN level, so we've gotten to the point now where we can run compute on a CDN you know, 10 years ago we could not do that. That was fringe technology to be able to. Run like basic, like there was, you know, there was conditional logic at some point that you could have done on a CDN with like Varnish or something I've never used because I was just not doing stuff like that at that point.

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Run like basic, like there was, you know, there was conditional logic at some point that you could have done on a CDN with like Varnish or something I've never used because I was just not doing stuff like that at that point. Now we got to the point where you can just write pure JavaScript on a CDN, which is insane if you don't know what a CDN is. It's just a network of computers that is copied all of its files all across the world, so you can get them faster. That's it.

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That's it. You're looking at this website on the CDN right now. That's what Edge function is. It's a programmable CDN background jobs.

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It's a programmable CDN background jobs. These are things that run in the background, you know, for instance, you try to go do something on a website it's like, hold on, we'll let you know when this is done. This is taking too long. That's a background job.

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That's a background job. They can't do it right now for whatever reason. Either it's gonna take too long they don't want you sitting there looking at it a bad experience or they have to queue it up for whatever reasons, costs, computes. Whatever, that's a background job a lot of those, I would say most background jobs have nothing to do with the user.

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Whatever, that's a background job a lot of those, I would say most background jobs have nothing to do with the user. A lot of the background jobs are just for like. Architecture stuff like honestly sometimes just fixing problems that engineers created themselves. I've seen a lot of background jobs of being like we made a background job to like fix this bug that we can't fix so we made a background job that just like resets this thing every day at 9 o'clock because we don't know what the issue is it's like oh OK cool so.

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I've seen a lot of background jobs of being like we made a background job to like fix this bug that we can't fix so we made a background job that just like resets this thing every day at 9 o'clock because we don't know what the issue is it's like oh OK cool so. That kind of brings me to cron jobs, which is a type of background job that runs on some type of interval so there is a spec specific Linux cron syntax that you can describe how long or what frequency you want this code to run. So, yeah, it's just scheduled tasks.

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So these are all like different backend types of things we're gonna be doing traditional long the servers