[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"me":3,"catalog:en:backend\u002Fnodejs-memory-performance":4,"config":253},null,{"field_key":5,"field_name":6,"seniority":7,"topic_key":8,"topic_name":9,"spec_key":7,"spec_name":7,"locale":10,"cell_total":11,"field_total":12,"seniorities":13,"topics":17,"specs":148,"samples":168},"backend","Backend","","nodejs-memory-performance","Nodejs Memory Performance","en",75,3300,[14,15,16],"junior","mid","senior",[18,21,24,27,30,33,36,39,42,45,48,51,54,57,60,63,66,69,72,75,78,81,84,87,90,93,96,97,100,103,106,109,112,115,118,121,124,127,130,133,136,139,142,145],{"key":19,"name":20,"count":11},"api-design","API Design",{"key":22,"name":23,"count":11},"caching","Caching",{"key":25,"name":26,"count":11},"concurrency","Concurrency",{"key":28,"name":29,"count":11},"csharp-concurrency-async","Csharp Concurrency Async",{"key":31,"name":32,"count":11},"csharp-exceptions","Csharp 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Async",{"key":110,"name":111,"count":11},"php-exceptions","Php Exceptions",{"key":113,"name":114,"count":11},"php-generics-interfaces","Php Generics Interfaces",{"key":116,"name":117,"count":11},"php-memory-performance","Php Memory Performance",{"key":119,"name":120,"count":11},"php-stdlib-http","Php Stdlib Http",{"key":122,"name":123,"count":11},"php-testing-tooling","Php Testing Tooling",{"key":125,"name":126,"count":11},"python-concurrency-async","Python Concurrency Async",{"key":128,"name":129,"count":11},"python-errors-context","Python Errors Context",{"key":131,"name":132,"count":11},"python-memory-performance","Python Memory Performance",{"key":134,"name":135,"count":11},"python-stdlib-http","Python Stdlib Http",{"key":137,"name":138,"count":11},"python-testing-tooling","Python Testing Tooling",{"key":140,"name":141,"count":11},"python-typing-oop","Python Typing Oop",{"key":143,"name":144,"count":11},"security","Security",{"key":146,"name":147,"count":11},"testing","Testing",[149,153,156,159,162,165],{"key":150,"name":151,"count":152},"csharp","C#\u002F.NET",450,{"key":154,"name":155,"count":152},"go","Go",{"key":157,"name":158,"count":152},"java","Java",{"key":160,"name":161,"count":152},"nodejs","Node.js",{"key":163,"name":164,"count":152},"php","PHP",{"key":166,"name":167,"count":152},"python","Python",[169,187,201,214,227,240],{"id":170,"topic":9,"difficulty":171,"body":172,"options":173,"correct_key":181,"explanation":186},"019f71b0-db58-71e2-9c81-1868fcb9da03",1,"In Node.js, what does `process.memoryUsage().heapUsed` represent?",[174,177,180,183],{"key":175,"text":176},"a","The total memory (RSS) the Node.js process occupies in the operating system, including buffers and native code",{"key":178,"text":179},"b","The maximum heap size Node.js is allowed to ever use, set by the `--max-old-space-size` flag",{"key":181,"text":182},"c","The amount of memory currently used by objects living on the V8 JavaScript heap",{"key":184,"text":185},"d","The amount of memory freed by the last garbage collection cycle","`heapUsed` reports the bytes currently occupied on V8's JavaScript heap at the moment the call is made — mostly live objects, though it can also include garbage not yet reclaimed by the next collection cycle. It is distinct from `rss` (the whole process's resident memory, including native buffers and code), `heapTotal` (memory V8 has allocated for the heap, whether used or not), and it is not a delta produced by garbage collection.",{"id":188,"topic":9,"difficulty":189,"body":190,"options":191,"correct_key":175,"explanation":200},"019f71b0-db58-7a5e-b652-2bcbdce35d40",2,"```javascript\nlet cache = {};\n\nfunction handleRequest(id, data) {\n  cache[id] = data;\n}\n```\nThis function is called on every incoming request with a unique `id`. Over a long-running server process, what is the most likely effect on memory?",[192,194,196,198],{"key":175,"text":193},"`cache` grows without bound since entries are never removed, keeping every `data` object reachable forever",{"key":178,"text":195},"None — objects assigned to a plain object's properties are automatically cleaned up once the request finishes",{"key":181,"text":197},"V8 automatically evicts the oldest entries once `cache` exceeds a fixed size limit",{"key":184,"text":199},"Only the most recent 100 entries are kept because V8's garbage collector caps object property counts","`cache` is a plain object referenced from module scope, so as long as the module is loaded, `cache` and everything assigned onto it stay reachable. Since `id` is unique per request and nothing ever deletes old keys, this is a classic unbounded-cache memory leak: memory usage climbs steadily with request volume.",{"id":202,"topic":9,"difficulty":189,"body":203,"options":204,"correct_key":175,"explanation":213},"019f71b0-db59-73de-bf4b-2c9e4c8e8790","```javascript\nfunction makeLogger() {\n  const bigBuffer = new Array(1000000).fill('x');\n  return function log(msg) {\n    console.log(msg);\n  };\n}\n\nconst logger = makeLogger();\n```\n`bigBuffer` is never used inside `log`. After `makeLogger()` returns and `logger` is kept alive, what happens to `bigBuffer`?",[205,207,209,211],{"key":175,"text":206},"It becomes eligible for garbage collection immediately, since `log` never references it",{"key":178,"text":208},"It is copied by value into `log`'s own private scope, so the original array sitting in `makeLogger` gets freed the moment the function returns",{"key":181,"text":210},"It is automatically moved to Node's old generation heap and frozen there, permanently, never eligible for collection again under any circumstance",{"key":184,"text":212},"It stays reachable via the closure's outer scope for as long as `logger` is reachable, even though `log` itself never touches it","A closure only keeps alive the specific variables it actually references, not every variable declared in its enclosing scope. V8 determines at compile time which outer variables a function body captures; since `log` never touches `bigBuffer`, V8 has no reason to keep it reachable through `log`'s closure. Once `makeLogger()` returns, `bigBuffer` has no other reference keeping it alive and becomes eligible for garbage collection immediately — this differs from the case where a sibling closure over the same scope *does* use the variable, which can keep it alive.",{"id":215,"topic":9,"difficulty":171,"body":216,"options":217,"correct_key":178,"explanation":226},"019f71b0-db5a-7610-ad65-6324c063a4c4","Which statement correctly describes memory management in Node.js?",[218,220,222,224],{"key":175,"text":219},"Developers must manually call `delete` on every object they create, or the process will crash",{"key":178,"text":221},"Memory is managed automatically by V8's garbage collector; there is no manual `free()`-style API for regular JS objects",{"key":181,"text":223},"Node.js requires calling `process.free(obj)` to release memory held by an object",{"key":184,"text":225},"Garbage collection is entirely optional in Node.js and must be explicitly enabled with a command-line flag before it will ever run at all","Node.js runs on V8, which manages memory automatically through garbage collection: objects are freed once they become unreachable, without any manual `free()`-style call from application code. There is no `process.free()` API, `delete` only removes an object property (not the object itself), and garbage collection is always on by default, not an opt-in feature.",{"id":228,"topic":9,"difficulty":189,"body":229,"options":230,"correct_key":175,"explanation":239},"019f71b0-db5a-7e38-8374-5bf7b691b57b","```javascript\nfunction startTicker() {\n  const state = { count: 0 };\n  setInterval(() => {\n    state.count++;\n  }, 1000);\n}\n\nstartTicker();\n```\n`startTicker()` is called once and its return value is discarded. What happens to `state` and the interval it created?",[231,233,235,237],{"key":175,"text":232},"The interval keeps running forever (unless cleared), and its callback's closure keeps `state` reachable indefinitely",{"key":178,"text":234},"Both are garbage collected right away, since nothing outside `startTicker` references them",{"key":181,"text":236},"Node.js automatically clears intervals that have no external reference to their return value",{"key":184,"text":238},"`state` is collected right after the very first tick fires, but the interval itself keeps running forever with `count` permanently fixed at 0","`setInterval` registers its callback with Node's timer subsystem, which holds a reference to that callback until `clearInterval` is called. Since the callback closes over `state`, `state` stays reachable through that closure for as long as the interval keeps firing — nothing here ever calls `clearInterval`, so both the timer and `state` live for the rest of the process's lifetime.",{"id":241,"topic":9,"difficulty":189,"body":242,"options":243,"correct_key":181,"explanation":252},"019f71b0-db5c-7c91-a665-3f0295594b46","```javascript\nconst { EventEmitter } = require('events');\nconst bus = new EventEmitter();\n\nfunction onRequest() {\n  bus.on('data', () => {\n    console.log('handling data');\n  });\n}\n\nfor (let i = 0; i \u003C 15; i++) {\n  onRequest();\n}\n```\nWhat is the most likely observable effect of running this loop?",[244,246,248,250],{"key":175,"text":245},"Nothing unusual happens at all — `EventEmitter` silently ignores any duplicate listener functions registered for the exact same event name",{"key":178,"text":247},"A `TypeError` is thrown synchronously the moment the 11th listener gets registered on that emitter instance",{"key":181,"text":249},"A `MaxListenersExceededWarning` is printed, since more than the default 10 listeners were added to the `'data'` event on one emitter",{"key":184,"text":251},"Only the first 10 listeners are kept; calls 11 through 15 are silently dropped","`EventEmitter` instances default to a maximum of 10 listeners per event, purely as a leak-detection heuristic. Registering the 11th listener for `'data'` on the same `bus` instance already exceeds that default and triggers a `MaxListenersExceededWarning` on the process's `stderr` — it is a warning, not an error, and every listener added (all 15 of them) is still kept and will still fire.",{"fields":254,"seniorities":424,"interview_shapes":425,"locales":430,"oauth":432,"question_count":435,"coach_enabled":436,"jd_match_enabled":436},[255,266,286,303,327,340,359,378,398,405,411,418],{"key":5,"name_tr":6,"name_en":6,"sort":171,"specializations":256},[257,260,261,262,263,264,265],{"key":258,"name":259,"field":5},"general","Genel",{"key":154,"name":155,"field":5},{"key":166,"name":167,"field":5},{"key":157,"name":158,"field":5},{"key":150,"name":151,"field":5},{"key":160,"name":161,"field":5},{"key":163,"name":164,"field":5},{"key":267,"name_tr":268,"name_en":268,"sort":189,"specializations":269},"frontend","Frontend",[270,271,274,277,280,283],{"key":258,"name":259,"field":267},{"key":272,"name":273,"field":267},"javascript","JavaScript",{"key":275,"name":276,"field":267},"typescript","TypeScript",{"key":278,"name":279,"field":267},"react","React",{"key":281,"name":282,"field":267},"vue","Vue",{"key":284,"name":285,"field":267},"angular","Angular",{"key":287,"name_tr":288,"name_en":288,"sort":289,"specializations":290},"fullstack","Fullstack",3,[291,292,293,294,295,296,297,298,299,300,301,302],{"key":258,"name":259,"field":287},{"key":154,"name":155,"field":5},{"key":166,"name":167,"field":5},{"key":157,"name":158,"field":5},{"key":150,"name":151,"field":5},{"key":160,"name":161,"field":5},{"key":163,"name":164,"field":5},{"key":272,"name":273,"field":267},{"key":275,"name":276,"field":267},{"key":278,"name":279,"field":267},{"key":281,"name":282,"field":267},{"key":284,"name":285,"field":267},{"key":304,"name_tr":305,"name_en":305,"sort":306,"specializations":307},"devops-cloud","DevOps \u002F Cloud",4,[308,309,312,315,318,321,324],{"key":258,"name":259,"field":304},{"key":310,"name":311,"field":304},"aws","AWS",{"key":313,"name":314,"field":304},"gcp","GCP",{"key":316,"name":317,"field":304},"azure","Azure",{"key":319,"name":320,"field":304},"kubernetes","Kubernetes",{"key":322,"name":323,"field":304},"terraform","Terraform",{"key":325,"name":326,"field":304},"linux","Linux",{"key":328,"name_tr":329,"name_en":329,"sort":330,"specializations":331},"ai-engineer","AI Engineer",5,[332,333,334,337],{"key":258,"name":259,"field":328},{"key":166,"name":167,"field":328},{"key":335,"name":336,"field":328},"llm-rag","LLM\u002FRAG",{"key":338,"name":339,"field":328},"mlops","MLOps",{"key":341,"name_tr":342,"name_en":343,"sort":344,"specializations":345},"database","Veritabanı","Database",6,[346,347,350,353,356],{"key":258,"name":259,"field":341},{"key":348,"name":349,"field":341},"postgresql","PostgreSQL",{"key":351,"name":352,"field":341},"mysql","MySQL",{"key":354,"name":355,"field":341},"mongodb","MongoDB",{"key":357,"name":358,"field":341},"redis","Redis",{"key":360,"name_tr":361,"name_en":362,"sort":363,"specializations":364},"mobile","Mobil","Mobile",7,[365,366,369,372,375],{"key":258,"name":259,"field":360},{"key":367,"name":368,"field":360},"ios-swift","iOS (Swift)",{"key":370,"name":371,"field":360},"android-kotlin","Android (Kotlin)",{"key":373,"name":374,"field":360},"flutter","Flutter",{"key":376,"name":377,"field":360},"react-native","React Native",{"key":143,"name_tr":379,"name_en":144,"sort":380,"specializations":381},"Güvenlik",8,[382,383,386,389,392,395],{"key":258,"name":259,"field":143},{"key":384,"name":385,"field":143},"appsec","AppSec",{"key":387,"name":388,"field":143},"offensive-pentest","Offensive \u002F Pentest",{"key":390,"name":391,"field":143},"cloud-security","Cloud Security",{"key":393,"name":394,"field":143},"devsecops","DevSecOps",{"key":396,"name":397,"field":143},"blue-team-incident","Blue Team \u002F Incident",{"key":399,"name_tr":400,"name_en":401,"sort":402,"specializations":403},"qa-test-automation","QA \u002F Test Otomasyonu","QA \u002F Test Automation",9,[404],{"key":258,"name":259,"field":399},{"key":406,"name_tr":407,"name_en":407,"sort":408,"specializations":409},"data-engineer","Data Engineer",10,[410],{"key":258,"name":259,"field":406},{"key":412,"name_tr":413,"name_en":414,"sort":415,"specializations":416},"game-dev","Oyun Geliştirme","Game Development",11,[417],{"key":258,"name":259,"field":412},{"key":419,"name_tr":420,"name_en":420,"sort":421,"specializations":422},"ml-engineer","ML Engineer",12,[423],{"key":258,"name":259,"field":419},[14,15,16],{"junior":426,"mid":428,"senior":429},{"questions":427,"median_sec":3},20,{"questions":427,"median_sec":3},{"questions":427,"median_sec":3},[431,10],"tr",[433,434],"google","github",21750,true]