{"id":4875,"date":"2026-09-04T23:46:42","date_gmt":"2026-09-04T18:16:42","guid":{"rendered":"https:\/\/itsupportwale.com\/blog\/best-way-to-learn-javascript-a-step-by-step-guide-for-2024\/"},"modified":"2026-09-04T23:46:42","modified_gmt":"2026-09-04T18:16:42","slug":"best-way-to-learn-javascript-a-step-by-step-guide-for-2024","status":"publish","type":"post","link":"https:\/\/itsupportwale.com\/blog\/best-way-to-learn-javascript-a-step-by-step-guide-for-2024\/","title":{"rendered":"Best Way to Learn JavaScript: A Step-by-Step Guide for 2024"},"content":{"rendered":"<p><strong>INCIDENT REPORT: #882-BRAVO-SIERRA<\/strong><br \/>\n<strong>STATUS:<\/strong> CRITICAL \/ SITE DOWN<br \/>\n<strong>DATE:<\/strong> 2024-05-14<br \/>\n<strong>SYSTEM:<\/strong> Payment Processing Gateway (Node.js v20.11.0)<br \/>\n<strong>ROOT CAUSE:<\/strong> Junior Developer &#8220;Chad&#8221; discovered <code>async\/await<\/code> but didn&#8217;t understand the Event Loop.<\/p>\n<hr \/>\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_80 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<label for=\"ez-toc-cssicon-toggle-item-6a9bde6e973d8\" class=\"ez-toc-cssicon-toggle-label\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/label><input type=\"checkbox\"  id=\"ez-toc-cssicon-toggle-item-6a9bde6e973d8\"  aria-label=\"Toggle\" \/><nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/itsupportwale.com\/blog\/best-way-to-learn-javascript-a-step-by-step-guide-for-2024\/#THE_LOGS_DONT_LIE\" >THE LOGS DON&#8217;T LIE<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/itsupportwale.com\/blog\/best-way-to-learn-javascript-a-step-by-step-guide-for-2024\/#1_THE_ILLUSION_OF_PROGRESS_AND_THE_NPM_ROT\" >1. THE ILLUSION OF PROGRESS AND THE NPM ROT<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/itsupportwale.com\/blog\/best-way-to-learn-javascript-a-step-by-step-guide-for-2024\/#2_THE_EVENT_LOOP_IS_NOT_A_SUGGESTION\" >2. THE EVENT LOOP IS NOT A SUGGESTION<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/itsupportwale.com\/blog\/best-way-to-learn-javascript-a-step-by-step-guide-for-2024\/#3_THE_%E2%80%98THIS_CONTEXT_A_COMEDY_OF_ERRORS\" >3. THE &#8216;THIS&#8217; CONTEXT: A COMEDY OF ERRORS<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/itsupportwale.com\/blog\/best-way-to-learn-javascript-a-step-by-step-guide-for-2024\/#4_TYPE_COERCION_THE_DARK_ALLEY_OF_ECMASCRIPT\" >4. TYPE COERCION: THE DARK ALLEY OF ECMASCRIPT<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/itsupportwale.com\/blog\/best-way-to-learn-javascript-a-step-by-step-guide-for-2024\/#5_MEMORY_LEAKS_AND_THE_MYTH_OF_AUTOMATIC_GC\" >5. MEMORY LEAKS AND THE MYTH OF AUTOMATIC GC<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/itsupportwale.com\/blog\/best-way-to-learn-javascript-a-step-by-step-guide-for-2024\/#6_STOP_HIDING_BEHIND_FRAMEWORKS\" >6. STOP HIDING BEHIND FRAMEWORKS<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/itsupportwale.com\/blog\/best-way-to-learn-javascript-a-step-by-step-guide-for-2024\/#7_THE_SPECIFICITY_OF_FAILURE_ES5_VS_ES2023\" >7. THE SPECIFICITY OF FAILURE: ES5 VS ES2023<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/itsupportwale.com\/blog\/best-way-to-learn-javascript-a-step-by-step-guide-for-2024\/#8_THE_RECONSTRUCTION_HOW_TO_ACTUALLY_CODE\" >8. THE RECONSTRUCTION: HOW TO ACTUALLY CODE<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/itsupportwale.com\/blog\/best-way-to-learn-javascript-a-step-by-step-guide-for-2024\/#9_THE_BITTER_TRUTH\" >9. THE BITTER TRUTH<\/a><\/li><\/ul><\/nav><\/div>\n<h3><span class=\"ez-toc-section\" id=\"THE_LOGS_DONT_LIE\"><\/span>THE LOGS DON&#8217;T LIE<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>I walked into the office at 3:00 AM because the pager went off. The production logs looked like a graveyard. Here is what I saw on the monitor before I even took a sip of my lukewarm, bitter coffee:<\/p>\n<pre class=\"codehilite\"><code class=\"language-bash\">[2024-05-14T03:02:11.452Z] ERROR: Payment processing stalled.\n[2024-05-14T03:02:15.881Z] FATAL ERROR: Reached heap limit Allocation failed - JavaScript heap out of memory\n 1: 0xb7a8e0 node::Abort() [node]\n 2: 0xa8fb0b  [node]\n 3: 0xd46490 v8::Utils::ReportOOMFailure(v8::internal::Isolate*, char const*, bool) [node]\n 4: 0xd46817 v8::internal::V8::FatalProcessOutOfMemory(v8::internal::Isolate*, char const*, bool) [node]\n 5: 0xf24025  [node]\n 6: 0xf3620f v8::internal::Heap::CollectGarbage(v8::internal::AllocationSpace, v8::internal::GarbageCollectionReason, v8::GCCallbackFlags) [node]\n...\n&lt;--- Last few GCs ---&gt;\n[14222:0x654e2c0]    15234 ms: Mark-sweep 2041.2 (2050.1) -&gt; 2041.1 (2050.1) MB, 112.4 \/ 0.0 ms  (average mu = 0.124, current mu = 0.002) allocation failure; GC in old space requested\n<\/code><\/pre>\n<p>And then, the final insult:<\/p>\n<pre class=\"codehilite\"><code class=\"language-bash\">npm ERR! code EADDRINUSE\nnpm ERR! syscall bind\nnpm ERR! address 0.0.0.0\nnpm ERR! port 3000\n<\/code><\/pre>\n<p>The system didn&#8217;t just crash; it choked to death. Chad, our latest &#8220;bootcamp ninja&#8221; who thinks TypeScript is a personality trait, decided to &#8220;refactor&#8221; the batch payment processor. He replaced a perfectly functional, battle-tested stream with a <code>Promise.all()<\/code> wrapper around an array of 50,000 database calls. <\/p>\n<p>He thought he was being &#8220;efficient.&#8221; He thought he was &#8220;leveraging the power of the cloud.&#8221; In reality, he was just flooding the microtask queue until the V8 engine\u2019s garbage collector gave up on life.<\/p>\n<hr \/>\n<h2><span class=\"ez-toc-section\" id=\"1_THE_ILLUSION_OF_PROGRESS_AND_THE_NPM_ROT\"><\/span>1. THE ILLUSION OF PROGRESS AND THE NPM ROT<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Most of you &#8220;developers&#8221; entering the field today are not learning JavaScript. You are learning how to glue together bloated packages you found on GitHub. You think that because you can <code>npx create-next-app<\/code> and see a spinning logo, you\u2019ve mastered the language. You haven&#8217;t. You\u2019ve just mastered the art of building a house of cards on a foundation of wet sand.<\/p>\n<p>The <strong>best way<\/strong> to learn JavaScript is to delete your <code>node_modules<\/code> folder and sit in a dark room until you can explain the difference between the Call Stack and the Task Queue without using a single buzzword.<\/p>\n<p>You treat <code>npm install<\/code> like a magic wand. Need to pad a string? <code>npm install left-pad<\/code>. Need to check if a number is even? <code>npm install is-even<\/code>. Every time you do this, you are importing thousands of lines of code you haven&#8217;t read, written by people you don&#8217;t know, to solve problems that require three lines of vanilla logic. You are creating a dependency graph that looks like a bowl of spaghetti and wondering why your build times are ten minutes long.<\/p>\n<p>The &#8220;ninjas&#8221; don&#8217;t understand that every dependency is a liability. They don&#8217;t understand that <code>v20.11.0<\/code> of Node handles memory differently than <code>v14<\/code>. They just want the &#8220;vibrant&#8221; experience of seeing green checkmarks in their terminal. Well, those green checkmarks don&#8217;t mean anything when the OOM (Out of Memory) killer comes for your production server at 3 AM.<\/p>\n<hr \/>\n<h2><span class=\"ez-toc-section\" id=\"2_THE_EVENT_LOOP_IS_NOT_A_SUGGESTION\"><\/span>2. THE EVENT LOOP IS NOT A SUGGESTION<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Let\u2019s look at the garbage Chad wrote. This was the &#8220;refactor&#8221; that cost us $40k in lost transactions:<\/p>\n<pre class=\"codehilite\"><code class=\"language-javascript\">\/\/ Chad's &quot;High Performance&quot; Processor\nasync function processPayments(payments) {\n  const results = payments.map(async (payment) =&gt; {\n    \/\/ This looks &quot;clean,&quot; right? Wrong.\n    const record = await db.find(payment.id);\n    const processed = await gateway.charge(record);\n    return processed;\n  });\n\n  return Promise.all(results);\n}\n<\/code><\/pre>\n<p>Do you see it? Probably not. You probably think this is &#8220;clean code.&#8221; <\/p>\n<p>Here is what actually happened: <code>payments.map<\/code> is synchronous. It doesn&#8217;t care that your callback is <code>async<\/code>. It iterates through all 50,000 items in the array instantly, firing off 50,000 Promises. These Promises all hit the microtask queue at the exact same time. The database driver, trying to be helpful, opens 50,000 socket connections. The OS, which actually has limits, starts screaming. The V8 heap tries to store the context for 50,000 pending operations, and\u2014<em>boom<\/em>\u2014the garbage collector (GC) starts thrashing.<\/p>\n<p>The GC tries to clear space, but it can&#8217;t, because all those Promises are still &#8220;in flight.&#8221; The &#8220;Mark-sweep&#8221; phase of the V8 engine (the part where it identifies what memory can be freed) takes longer and longer. Eventually, the &#8220;mutator utilization&#8221; (the time the CPU spends actually running your code vs. cleaning up your mess) drops to near zero.<\/p>\n<p>The <strong>best way<\/strong> to learn is to understand that JavaScript is single-threaded. It\u2019s a one-lane road. If you try to drive 50,000 trucks down it at once, you don&#8217;t get there faster; you just cause a pile-up. You should have used a pool. You should have used a stream. You should have understood that <code>await<\/code> inside a <code>map<\/code> is a recipe for disaster unless you\u2019re controlling the concurrency.<\/p>\n<hr \/>\n<h2><span class=\"ez-toc-section\" id=\"3_THE_%E2%80%98THIS_CONTEXT_A_COMEDY_OF_ERRORS\"><\/span>3. THE &#8216;THIS&#8217; CONTEXT: A COMEDY OF ERRORS<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>If I ask a junior to explain <code>this<\/code> in JavaScript, they usually start sweating. They think it\u2019s &#8220;magic.&#8221; It\u2019s not magic; it\u2019s just poorly designed, and you have to deal with it.<\/p>\n<p>Look at this broken snippet I found in our &#8220;user dashboard&#8221; component:<\/p>\n<pre class=\"codehilite\"><code class=\"language-javascript\">const UIController = {\n  buttonLabel: &quot;Submit&quot;,\n  init: function() {\n    const btn = document.getElementById('submit-btn');\n    btn.addEventListener('click', function() {\n      console.log(&quot;Clicking: &quot; + this.buttonLabel); \/\/ Result: Clicking: undefined\n    });\n  }\n};\n<\/code><\/pre>\n<p>Chad spent three hours trying to figure out why <code>this.buttonLabel<\/code> was <code>undefined<\/code>. He tried to use <code>var self = this;<\/code>. He tried to use <code>.bind(this)<\/code>. He eventually just gave up and hardcoded the string.<\/p>\n<p>The problem is that he doesn&#8217;t understand <em>execution context<\/em>. In a regular function, <code>this<\/code> is determined by <em>how the function is called<\/em>. When the DOM calls that event listener, <code>this<\/code> is no longer <code>UIController<\/code>; it\u2019s the <code>HTMLButtonElement<\/code>. <\/p>\n<p>If you want to fix it, you use an arrow function, because arrow functions don&#8217;t have their own <code>this<\/code>. They capture it from the lexical scope.<\/p>\n<pre class=\"codehilite\"><code class=\"language-javascript\">\/\/ Fixed, but Chad doesn't know why\nbtn.addEventListener('click', () =&gt; {\n  console.log(&quot;Clicking: &quot; + this.buttonLabel);\n});\n<\/code><\/pre>\n<p>But wait! If <code>UIController.init<\/code> was also an arrow function, <code>this<\/code> would be the <code>window<\/code> object (or <code>global<\/code> in Node). You have to actually <em>know<\/em> the rules of the language. You can&#8217;t just guess until the linter stops complaining.<\/p>\n<hr \/>\n<h2><span class=\"ez-toc-section\" id=\"4_TYPE_COERCION_THE_DARK_ALLEY_OF_ECMASCRIPT\"><\/span>4. TYPE COERCION: THE DARK ALLEY OF ECMASCRIPT<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>You think you know how to compare values? You don&#8217;t. You rely on <code>===<\/code> because some <a href=\"https:\/\/itsupportwale.com\/blog\/\" title=\"Read more about blog\">blog<\/a> post told you <code>==<\/code> is &#8220;evil.&#8221; While <code>===<\/code> is safer, not knowing <em>why<\/em> <code>==<\/code> behaves the way it does is a sign of intellectual laziness.<\/p>\n<p>Explain this to me, &#8220;ninja&#8221;:<br \/>\n<code>[] == ![]<\/code> evaluates to <code>true<\/code>.<\/p>\n<p>Why? Because the language is a series of historical accidents held together by duct tape.<br \/>\n1. The <code>!<\/code> operator has higher precedence, so <code>![]<\/code> becomes <code>false<\/code>.<br \/>\n2. Now we have <code>[] == false<\/code>.<br \/>\n3. The abstract equality algorithm sees an object and a boolean. It tries to convert the boolean to a number. <code>false<\/code> becomes <code>0<\/code>.<br \/>\n4. Now we have <code>[] == 0<\/code>.<br \/>\n5. The algorithm tries to convert the object to a primitive. For an empty array, that\u2019s an empty string <code>\"\"<\/code>.<br \/>\n6. Now we have <code>\"\" == 0<\/code>.<br \/>\n7. The algorithm converts the string to a number. <code>\"\"<\/code> becomes <code>0<\/code>.<br \/>\n8. <code>0 == 0<\/code> is <code>true<\/code>.<\/p>\n<p>If you don&#8217;t understand the underlying mechanics of type coercion, you will eventually write a bug that only happens when a user enters the number <code>0<\/code> into a text field, and your &#8220;clever&#8221; <code>if (input)<\/code> check fails because <code>0<\/code> is falsy.<\/p>\n<p>The <strong>best way<\/strong> to avoid being a liability is to read the ECMAScript specification. Yes, the actual spec. It\u2019s dry, it\u2019s boring, and it\u2019s the only thing that matters. Everything else is just someone\u2019s opinion.<\/p>\n<hr \/>\n<h2><span class=\"ez-toc-section\" id=\"5_MEMORY_LEAKS_AND_THE_MYTH_OF_AUTOMATIC_GC\"><\/span>5. MEMORY LEAKS AND THE MYTH OF AUTOMATIC GC<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>&#8220;JavaScript has a garbage collector, so I don&#8217;t have to worry about memory.&#8221; <\/p>\n<p>This is the lie that kills servers. I\u2019ve spent the last decade hunting down memory leaks caused by people who think closures are free. Closures are not free. They are memory anchors.<\/p>\n<p>Look at this &#8220;logger&#8221; Chad wrote:<\/p>\n<pre class=\"codehilite\"><code class=\"language-javascript\">function createLogger() {\n  const massiveData = new Array(1000000).fill('garbage');\n  return function(msg) {\n    console.log(msg);\n    \/\/ massiveData is still in scope, so it's never collected.\n  };\n}\n\nconst myLog = createLogger();\n<\/code><\/pre>\n<p>Chad thinks that because he\u2019s not using <code>massiveData<\/code> inside the returned function, the V8 engine is smart enough to throw it away. It isn&#8217;t. The returned function maintains a reference to the entire lexical environment in which it was created. As long as <code>myLog<\/code> exists, that million-element array stays in the heap.<\/p>\n<p>Now imagine Chad puts this inside a request handler. Every time a user hits the home page, a new million-element array is allocated and never freed. This is why our Node process went from 100MB to 2GB in twenty minutes.<\/p>\n<p>In the Chromium engine (and by extension, Node), the heap is divided into &#8220;New Space&#8221; and &#8220;Old Space.&#8221; New Space is small and fast; it\u2019s where objects are born. If they survive a few rounds of GC, they get promoted to Old Space. Once they are in Old Space, the GC is much more expensive to run. If you keep leaking closures, you fill up Old Space until the engine starts &#8220;Stop-the-world&#8221; garbage collection, where your entire application freezes for several seconds just to try and find a few bytes of memory.<\/p>\n<hr \/>\n<h2><span class=\"ez-toc-section\" id=\"6_STOP_HIDING_BEHIND_FRAMEWORKS\"><\/span>6. STOP HIDING BEHIND FRAMEWORKS<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>I see resumes every day that say &#8220;React Developer&#8221; or &#8220;Vue Expert.&#8221; These people can&#8217;t write a basic <code>fetch<\/code> request without a library. They don&#8217;t know how the DOM actually works. They think &#8220;Virtual DOM&#8221; is a feature of the language.<\/p>\n<p>If you don&#8217;t understand the difference between a <code>NodeList<\/code> and an <code>Array<\/code>, you aren&#8217;t a developer; you&#8217;re a framework-operator. If you don&#8217;t know that <code>document.querySelectorAll<\/code> returns a static list while <code>document.getElementsByClassName<\/code> returns a live one, you are going to write bugs that are impossible to debug.<\/p>\n<p>The &#8220;modern&#8221; web is a nightmare of abstractions. You\u2019re using a meta-framework (Next.js) built on a framework (React) built on a library (Scheduler) running on a runtime (Node\/V8) that\u2019s trying to emulate a browser environment. When something goes wrong, you have no idea where the failure is because you\u2019ve never seen the &#8220;raw&#8221; language.<\/p>\n<p>You think <code>useEffect<\/code> is a lifecycle hook. It\u2019s not. It\u2019s a synchronization mechanism that you are almost certainly using incorrectly to fetch data, causing infinite re-render loops that melt your users&#8217; MacBooks.<\/p>\n<hr \/>\n<h2><span class=\"ez-toc-section\" id=\"7_THE_SPECIFICITY_OF_FAILURE_ES5_VS_ES2023\"><\/span>7. THE SPECIFICITY OF FAILURE: ES5 VS ES2023<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>You kids have it easy. You have <code>class<\/code> syntax. You have <code>optional chaining<\/code>. You have <code>nullish coalescing<\/code>. You don&#8217;t remember the days of <code>prototype<\/code> chains and <code>arguments.callee<\/code>. But because you don&#8217;t know where the language came from, you don&#8217;t understand why it is the way it is.<\/p>\n<p>You use <code>const<\/code> and think it makes your variables immutable. It doesn&#8217;t.<\/p>\n<pre class=\"codehilite\"><code class=\"language-javascript\">const user = { name: 'Chad' };\nuser.name = 'Incompetent'; \/\/ This works fine.\n<\/code><\/pre>\n<p>You don&#8217;t understand the &#8220;Temporal Dead Zone.&#8221; You think <code>let<\/code> and <code>const<\/code> don&#8217;t hoist. They <em>do<\/em> hoist, but they aren&#8217;t initialized. If you try to access them before the declaration, you get a <code>ReferenceError<\/code>. <code>var<\/code>, on the other hand, hoists and initializes to <code>undefined<\/code>. This is the kind of fundamental knowledge that separates a professional from a hobbyist.<\/p>\n<p>And don&#8217;t get me started on the <code>npm<\/code> ecosystem. We had a vulnerability last week in a sub-dependency of a sub-dependency of a testing library we only use in development. Why? Because some developer decided that <code>is-promise<\/code> needed to be its own package, and then they broke the export format. <\/p>\n<p>The &#8220;best way&#8221; to learn is to look at the source code of your dependencies. Open <code>node_modules<\/code>. Read the code. You\u2019ll realize that half of the &#8220;senior&#8221; developers out there are writing code that is just as bad as yours.<\/p>\n<hr \/>\n<h2><span class=\"ez-toc-section\" id=\"8_THE_RECONSTRUCTION_HOW_TO_ACTUALLY_CODE\"><\/span>8. THE RECONSTRUCTION: HOW TO ACTUALLY CODE<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>If I were to rewrite Chad\u2019s payment processor, I wouldn&#8217;t use any &#8220;magic.&#8221; I\u2019d use a simple async generator or a controlled concurrency limit. I\u2019d respect the hardware. I\u2019d respect the engine.<\/p>\n<pre class=\"codehilite\"><code class=\"language-javascript\">\/\/ A professional's approach\nasync function processPaymentsSafely(payments, batchSize = 10) {\n  const results = [];\n\n  for (let i = 0; i &lt; payments.length; i += batchSize) {\n    const batch = payments.slice(i, i + batchSize);\n\n    \/\/ Process a small batch in parallel, but don't overwhelm the system\n    const batchResults = await Promise.all(batch.map(async (payment) =&gt; {\n      try {\n        const record = await db.find(payment.id);\n        return await gateway.charge(record);\n      } catch (err) {\n        console.error(`Failed to process ${payment.id}:`, err.message);\n        return { error: true, id: payment.id };\n      }\n    }));\n\n    results.push(...batchResults);\n\n    \/\/ Explicitly allow the event loop to breathe if this is a massive set\n    \/\/ This prevents blocking the main thread for too long\n    await new Promise(resolve =&gt; setImmediate(resolve));\n  }\n\n  return results;\n}\n<\/code><\/pre>\n<p>Notice the <code>setImmediate<\/code>. Notice the <code>try\/catch<\/code> <em>inside<\/em> the map. Notice the batching. This code won&#8217;t win any &#8220;ninja&#8221; awards for brevity, but it also won&#8217;t wake me up at 3 AM.<\/p>\n<p>It uses <code>setImmediate<\/code> (a Node-specific API) to push the next iteration to the end of the check phase of the event loop. This ensures that if there are other pending I\/O operations or timers, they get a chance to run. It prevents &#8220;Starvation.&#8221;<\/p>\n<hr \/>\n<h2><span class=\"ez-toc-section\" id=\"9_THE_BITTER_TRUTH\"><\/span>9. THE BITTER TRUTH<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>You want the &#8220;best way&#8221; to learn? Fine. Here it is:<\/p>\n<ol>\n<li><strong>Stop watching tutorials.<\/strong> They are designed to make you feel smart while teaching you nothing. They show you a &#8220;seamless&#8221; path that doesn&#8217;t exist in reality.<\/li>\n<li><strong>Build something without a framework.<\/strong> Write a web server using only the Node <code>http<\/code> module. Write a frontend using only <code>document.createElement<\/code>. You will hate it. You will realize how much work the frameworks are doing. And then, you will finally understand <em>why<\/em> the frameworks exist.<\/li>\n<li><strong>Read the documentation.<\/strong> Not the &#8220;getting started&#8221; guide. The API reference. Read the V8 blog to understand how the JIT (Just-In-Time) compiler works. Understand &#8220;Hidden Classes&#8221; and why you should never delete properties from an object if you want it to stay fast.<\/li>\n<li><strong>Break things.<\/strong> Intentionally cause a memory leak. Intentionally block the event loop. Use <code>node --inspect<\/code> and open Chrome DevTools to look at the heap snapshot. Look at the &#8220;Retainers&#8221; tree. See what\u2019s keeping your objects alive.<\/li>\n<li><strong>Learn the history.<\/strong> Understand the difference between ES5 (the dark ages), ES6 (the renaissance), and the yearly releases we have now. Understand why <code>Symbol<\/code> was added and what &#8220;Iterables&#8221; actually are.<\/li>\n<\/ol>\n<p>JavaScript is a beautiful, terrible, powerful, and fragile language. It is the engine of the modern world, and it is being driven by people who don&#8217;t know how a transmission works. <\/p>\n<p>Don&#8217;t be a Chad. Don&#8217;t be a &#8220;ninja.&#8221; Be an engineer. Learn the fundamentals until they hurt. Because when the server crashes and the logs are screaming, &#8220;vibrant&#8221; abstractions won&#8217;t save you. Only the truth will.<\/p>\n<p>Now, get out of my office and go fix that memory leak in the auth service. I can smell the heap thrashing from here.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>INCIDENT REPORT: #882-BRAVO-SIERRA STATUS: CRITICAL \/ SITE DOWN DATE: 2024-05-14 SYSTEM: Payment Processing Gateway (Node.js v20.11.0) ROOT CAUSE: Junior Developer &#8220;Chad&#8221; discovered async\/await but didn&#8217;t understand the Event Loop. THE LOGS DON&#8217;T LIE I walked into the office at 3:00 AM because the pager went off. The production logs looked like a graveyard. Here is &#8230; <a title=\"Best Way to Learn JavaScript: A Step-by-Step Guide for 2024\" class=\"read-more\" href=\"https:\/\/itsupportwale.com\/blog\/best-way-to-learn-javascript-a-step-by-step-guide-for-2024\/\" aria-label=\"Read more  on Best Way to Learn JavaScript: A Step-by-Step Guide for 2024\">Read more<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-4875","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.0 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Best Way to Learn JavaScript: A Step-by-Step Guide for 2024 - ITSupportWale<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/itsupportwale.com\/blog\/best-way-to-learn-javascript-a-step-by-step-guide-for-2024\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Best Way to Learn JavaScript: A Step-by-Step Guide for 2024 - ITSupportWale\" \/>\n<meta property=\"og:description\" content=\"INCIDENT REPORT: #882-BRAVO-SIERRA STATUS: CRITICAL \/ SITE DOWN DATE: 2024-05-14 SYSTEM: Payment Processing Gateway (Node.js v20.11.0) ROOT CAUSE: Junior Developer &#8220;Chad&#8221; discovered async\/await but didn&#8217;t understand the Event Loop. 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