[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"me":3,"catalog:en:frontend\u002Fjavascript-runtime-apis":4,"config":234},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":133,"samples":150},"frontend","Frontend","","javascript-runtime-apis","Javascript Runtime Apis","en",75,2925,[14,15,16],"junior","mid","senior",[18,21,24,27,30,33,36,39,42,45,48,51,54,57,60,61,64,67,70,73,76,79,82,85,88,91,94,97,100,103,106,109,112,115,118,121,124,127,130],{"key":19,"name":20,"count":11},"accessibility","Accessibility",{"key":22,"name":23,"count":11},"angular-change-detection","Angular Change Detection",{"key":25,"name":26,"count":11},"angular-components-lifecycle","Angular Components Lifecycle",{"key":28,"name":29,"count":11},"angular-dependency-injection","Angular Dependency Injection",{"key":31,"name":32,"count":11},"angular-directives-pipes","Angular Directives Pipes",{"key":34,"name":35,"count":11},"angular-router-forms","Angular Router Forms",{"key":37,"name":38,"count":11},"angular-testing-performance","Angular Testing Performance",{"key":40,"name":41,"count":11},"css-layout","Css Layout",{"key":43,"name":44,"count":11},"dom-browser-apis","Dom Browser Apis",{"key":46,"name":47,"count":11},"javascript-async-concurrency","Javascript Async Concurrency",{"key":49,"name":50,"count":11},"javascript-language","Javascript Language",{"key":52,"name":53,"count":11},"javascript-memory-performance","Javascript Memory Performance",{"key":55,"name":56,"count":11},"javascript-modules-bundling","Javascript Modules Bundling",{"key":58,"name":59,"count":11},"javascript-prototypes-oop","Javascript Prototypes Oop",{"key":8,"name":9,"count":11},{"key":62,"name":63,"count":11},"javascript-testing-tooling","Javascript Testing Tooling",{"key":65,"name":66,"count":11},"performance","Performance",{"key":68,"name":69,"count":11},"react-components-jsx","React Components Jsx",{"key":71,"name":72,"count":11},"react-context-state","React Context State",{"key":74,"name":75,"count":11},"react-effects-lifecycle","React Effects Lifecycle",{"key":77,"name":78,"count":11},"react-forms-suspense","React Forms Suspense",{"key":80,"name":81,"count":11},"react-hooks-state","React Hooks State",{"key":83,"name":84,"count":11},"react-rendering-performance","React Rendering Performance",{"key":86,"name":87,"count":11},"rendering-reactivity","Rendering Reactivity",{"key":89,"name":90,"count":11},"state-management","State Management",{"key":92,"name":93,"count":11},"testing","Testing",{"key":95,"name":96,"count":11},"typescript-advanced-types","Typescript Advanced Types",{"key":98,"name":99,"count":11},"typescript-generics","Typescript Generics",{"key":101,"name":102,"count":11},"typescript-modules-declarations","Typescript Modules Declarations",{"key":104,"name":105,"count":11},"typescript-narrowing-control-flow","Typescript Narrowing Control Flow",{"key":107,"name":108,"count":11},"typescript-tooling-config","Typescript Tooling Config",{"key":110,"name":111,"count":11},"typescript-type-fundamentals","Typescript Type Fundamentals",{"key":113,"name":114,"count":11},"vue-components-props","Vue Components Props",{"key":116,"name":117,"count":11},"vue-composition-api","Vue Composition Api",{"key":119,"name":120,"count":11},"vue-directives-templates","Vue Directives Templates",{"key":122,"name":123,"count":11},"vue-performance-testing","Vue Performance Testing",{"key":125,"name":126,"count":11},"vue-reactivity-system","Vue Reactivity System",{"key":128,"name":129,"count":11},"vue-router-state-management","Vue Router State Management",{"key":131,"name":132,"count":11},"web-security","Web Security",[134,138,141,144,147],{"key":135,"name":136,"count":137},"angular","Angular",450,{"key":139,"name":140,"count":137},"javascript","JavaScript",{"key":142,"name":143,"count":137},"react","React",{"key":145,"name":146,"count":137},"typescript","TypeScript",{"key":148,"name":149,"count":137},"vue","Vue",[151,169,182,195,208,221],{"id":152,"topic":9,"difficulty":153,"body":154,"options":155,"correct_key":160,"explanation":168},"019f7517-0fa5-74df-a050-ca7d3724383e",1,"What is the main advantage of `Map` over a plain object when you need to use non-string values as keys?",[156,159,162,165],{"key":157,"text":158},"a","`Map` automatically converts keys to strings, just like objects",{"key":160,"text":161},"b","`Map` allows any value (objects, functions, numbers) to be used as a key without coercion",{"key":163,"text":164},"c","`Map` only accepts numeric keys, which makes lookups faster",{"key":166,"text":167},"d","`Map` keys are always converted to `Symbol`s internally","A plain object coerces every key to a string (or `Symbol`), so `obj[{}]` and `obj[1]` both end up as string keys. `Map` keeps keys as-is — an object reference, a number, a boolean, even `NaN` — with no coercion. Option (a) describes object behavior, not Map's advantage. Option (c) and (d) are simply false.",{"id":170,"topic":9,"difficulty":153,"body":171,"options":172,"correct_key":163,"explanation":181},"019f7517-0fa6-7d4e-a52e-633ca84ab0df","```javascript\nconst user = { name: 'Ada', address: { city: 'London' } };\nconsole.log(user.address?.city);\nconsole.log(user.contact?.email);\n```\nWhat does this print?",[173,175,177,179],{"key":157,"text":174},"`undefined` then `undefined`",{"key":160,"text":176},"`London` then throws a `TypeError`",{"key":163,"text":178},"`London` then `undefined`",{"key":166,"text":180},"throws a `TypeError` on the first line","`user.address` exists, so `?.city` just reads `city` normally → `'London'`. `user.contact` is `undefined`, so `?.email` short-circuits instead of throwing and evaluates to `undefined` — this is exactly what optional chaining is for: avoiding a manual `user.contact && user.contact.email` check.",{"id":183,"topic":9,"difficulty":153,"body":184,"options":185,"correct_key":157,"explanation":194},"019f7517-0fa7-7721-bf91-6334e3d612fa","```javascript\nfunction getPort(config) {\n  return config.port ?? 8080;\n}\nconsole.log(getPort({ port: 0 }));\nconsole.log(getPort({}));\n```\nWhat does this print?",[186,188,190,192],{"key":157,"text":187},"`0` then `8080`",{"key":160,"text":189},"`8080` then `8080`",{"key":163,"text":191},"`0` then `undefined`",{"key":166,"text":193},"`8080` then `undefined`","`??` (nullish coalescing) only falls back to the right-hand side when the left side is `null` or `undefined` — `0` is neither, so `config.port ?? 8080` correctly returns `0` for the first call. For `{}`, `config.port` is `undefined`, so it falls back to `8080`. This is the classic case where `||` would have been a bug, since `0 || 8080` would incorrectly produce `8080`.",{"id":196,"topic":9,"difficulty":153,"body":197,"options":198,"correct_key":166,"explanation":207},"019f7517-0fa7-7ea0-bdcd-d85fcb988457","```javascript\nconst original = [1, 2, 3];\nconst copy = [...original];\ncopy.push(4);\nconsole.log(original.length, copy.length);\n```\nWhat does this print?",[199,201,203,205],{"key":157,"text":200},"`4 4`",{"key":160,"text":202},"`3 3`",{"key":163,"text":204},"`4 3`",{"key":166,"text":206},"`3 4`","The spread operator `[...original]` creates a new array with the same elements copied in — `copy` and `original` are separate arrays after this. Pushing to `copy` only changes `copy`'s length (4), while `original` stays untouched at length 3.",{"id":209,"topic":9,"difficulty":153,"body":210,"options":211,"correct_key":160,"explanation":220},"019f7517-0fa8-7ebf-acf8-b45343aeb1eb","What is the defining feature of a `Set` in JavaScript?",[212,214,216,218],{"key":157,"text":213},"It stores key-value pairs like `Map`, but with faster lookup",{"key":160,"text":215},"It stores only unique values and preserves insertion order when iterated",{"key":163,"text":217},"It automatically sorts its values in ascending order",{"key":166,"text":219},"It can only hold primitive values, not objects","`Set` is a collection of unique values — adding a duplicate is a no-op — and iterating it (via `for...of`, spread, or `.forEach`) yields values in insertion order. It does not sort values, and it can hold objects as well as primitives, so (c) and (d) are wrong. (a) confuses `Set` with `Map`.",{"id":222,"topic":9,"difficulty":153,"body":223,"options":224,"correct_key":163,"explanation":233},"019f7517-0fa9-7c06-bda4-5eccd891db08","```javascript\nconst point = { x: 1, y: 2, z: 3 };\nconst { x, ...rest } = point;\nconsole.log(x, rest);\n```\nWhat does this print?",[225,227,229,231],{"key":157,"text":226},"`1 { x: 1, y: 2, z: 3 }`",{"key":160,"text":228},"`undefined { y: 2, z: 3 }`",{"key":163,"text":230},"`1 { y: 2, z: 3 }`",{"key":166,"text":232},"`{ x: 1 } { y: 2, z: 3 }`","In object destructuring, `x` pulls out the `x` property (`1`), and `...rest` collects everything else that wasn't already destructured into a new plain object `{ y: 2, z: 3 }`. `x` itself is bound to the primitive value `1`, not an object.",{"fields":235,"seniorities":410,"interview_shapes":411,"locales":416,"oauth":418,"question_count":421,"coach_enabled":422,"jd_match_enabled":422},[236,261,270,287,311,324,343,362,384,391,397,404],{"key":237,"name_tr":238,"name_en":238,"sort":153,"specializations":239},"backend","Backend",[240,243,246,249,252,255,258],{"key":241,"name":242,"field":237},"general","Genel",{"key":244,"name":245,"field":237},"go","Go",{"key":247,"name":248,"field":237},"python","Python",{"key":250,"name":251,"field":237},"java","Java",{"key":253,"name":254,"field":237},"csharp","C#\u002F.NET",{"key":256,"name":257,"field":237},"nodejs","Node.js",{"key":259,"name":260,"field":237},"php","PHP",{"key":5,"name_tr":6,"name_en":6,"sort":262,"specializations":263},2,[264,265,266,267,268,269],{"key":241,"name":242,"field":5},{"key":139,"name":140,"field":5},{"key":145,"name":146,"field":5},{"key":142,"name":143,"field":5},{"key":148,"name":149,"field":5},{"key":135,"name":136,"field":5},{"key":271,"name_tr":272,"name_en":272,"sort":273,"specializations":274},"fullstack","Fullstack",3,[275,276,277,278,279,280,281,282,283,284,285,286],{"key":241,"name":242,"field":271},{"key":244,"name":245,"field":237},{"key":247,"name":248,"field":237},{"key":250,"name":251,"field":237},{"key":253,"name":254,"field":237},{"key":256,"name":257,"field":237},{"key":259,"name":260,"field":237},{"key":139,"name":140,"field":5},{"key":145,"name":146,"field":5},{"key":142,"name":143,"field":5},{"key":148,"name":149,"field":5},{"key":135,"name":136,"field":5},{"key":288,"name_tr":289,"name_en":289,"sort":290,"specializations":291},"devops-cloud","DevOps \u002F Cloud",4,[292,293,296,299,302,305,308],{"key":241,"name":242,"field":288},{"key":294,"name":295,"field":288},"aws","AWS",{"key":297,"name":298,"field":288},"gcp","GCP",{"key":300,"name":301,"field":288},"azure","Azure",{"key":303,"name":304,"field":288},"kubernetes","Kubernetes",{"key":306,"name":307,"field":288},"terraform","Terraform",{"key":309,"name":310,"field":288},"linux","Linux",{"key":312,"name_tr":313,"name_en":313,"sort":314,"specializations":315},"ai-engineer","AI 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