docs(10_Wiki): W3Schools 위키화 — HTML/CSS/JavaScript(core)
W3Schools 튜토리얼을 P-Reinforce v3.1 포맷으로 위키화(영어 본문, 한/영 섹션 헤더). - Topic_HTML: 59문서 (튜토리얼+예제, 레퍼런스/메타 제외) - Topic_CSS: 190문서 (메인 + Advanced/Flexbox/Grid/RWD 전체) - Topic_JavaScript: 120문서 (코어 언어; Temporal/DOM상세/BOM/WebAPI/AJAX/jQuery/Graphics 등은 후속) 각 폴더 00_INDEX.md(MOC) 포함. 코드 verbatim, 미확인분은 "Not found in source" 표기. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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id: javascript-number-properties
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title: "JavaScript Number Properties"
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category: "Frontend"
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status: "draft"
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verification_status: "conceptual"
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canonical_id: ""
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aliases: ["Number properties", "Number.MAX_VALUE", "Number.EPSILON", "MAX_SAFE_INTEGER", "POSITIVE_INFINITY", "Number.NaN"]
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duplicate_of: ""
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source_trust_level: "B"
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confidence_score: 0.88
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created_at: 2026-06-23
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updated_at: 2026-06-23
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review_reason: ""
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merge_history: []
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tags: ["javascript", "js", "web", "frontend", "w3schools", "number", "constants"]
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raw_sources: ["https://www.w3schools.com/js/js_number_properties.asp"]
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applied_in: []
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github_commit: ""
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---
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# [[JavaScript Number Properties]]
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## 🎯 한 줄 통찰 (One-line insight)
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JavaScript Number properties are static constants on the `Number` object that expose the limits of the language's numeric type — its largest, smallest, safe-integer bounds, infinities, and the not-a-number value. [S1]
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## 🧠 핵심 개념 (Core concepts)
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- **Number properties are static** — they belong to the `Number` object itself and can only be accessed as `Number.PROPERTY` (for example `Number.MAX_VALUE`), never through a number variable or instance. [S1]
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- **EPSILON** is the difference between 1 and the smallest floating-point number greater than 1. [S1]
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- **MAX_VALUE / MIN_VALUE** are the largest and lowest possible numbers in JavaScript. [S1]
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- **MAX_SAFE_INTEGER / MIN_SAFE_INTEGER** are `2⁵³ − 1` and `−(2⁵³ − 1)` — the bounds of integers that can be represented exactly. [S1]
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- **POSITIVE_INFINITY / NEGATIVE_INFINITY** are returned on numeric overflow (for example `1 / 0` and `-1 / 0`). [S1]
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- **NaN** ("Not a Number") is returned by invalid arithmetic such as dividing a number by a non-numeric string. [S1]
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## 🧩 추출된 패턴 (Extracted patterns)
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- **Static access only** — reach a property as `Number.MAX_VALUE`; reading the same name off a variable (`x.MAX_VALUE`) yields `undefined`. [S1]
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- **Overflow → Infinity** — operations that exceed the representable range produce `Infinity` rather than throwing an error. [S1]
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- **Invalid arithmetic → NaN** — mixing a number with a non-numeric string in arithmetic produces `NaN`. [S1]
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## 📖 세부 내용 (Details)
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Number properties belong to the JavaScript `Number` object. These properties can only be accessed as `Number.MAX_VALUE` (statically), not on a variable. [S1]
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**JavaScript EPSILON** — the difference between 1 and the smallest floating-point number greater than 1: [S1]
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```javascript
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let x = Number.EPSILON;
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```
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**JavaScript MAX_VALUE** — the largest possible number in JavaScript: [S1]
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```javascript
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let x = Number.MAX_VALUE;
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```
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**Number Properties Cannot be Used on Variables** — accessing a property name on a number variable returns `undefined`: [S1]
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```javascript
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let x = 6;
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x.MAX_VALUE
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```
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**JavaScript MIN_VALUE** — the lowest possible number in JavaScript: [S1]
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```javascript
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let x = Number.MIN_VALUE;
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```
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**JavaScript MIN_SAFE_INTEGER** — `−(2⁵³ − 1)`: [S1]
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```javascript
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let x = Number.MIN_SAFE_INTEGER;
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```
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**JavaScript MAX_SAFE_INTEGER** — `2⁵³ − 1`: [S1]
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```javascript
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let x = Number.MAX_SAFE_INTEGER;
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```
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**JavaScript POSITIVE_INFINITY** — accessed as a property: [S1]
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```javascript
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let x = Number.POSITIVE_INFINITY;
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```
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`POSITIVE_INFINITY` is returned on overflow: [S1]
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```javascript
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let x = 1 / 0;
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```
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**JavaScript NEGATIVE_INFINITY** — accessed as a property: [S1]
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```javascript
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let x = Number.NEGATIVE_INFINITY;
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```
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`NEGATIVE_INFINITY` is returned on overflow: [S1]
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```javascript
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let x = -1 / 0;
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```
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**JavaScript NaN — Not a Number** — accessed as a property: [S1]
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```javascript
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let x = Number.NaN;
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```
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`NaN` also results from invalid arithmetic, such as dividing by a non-numeric string: [S1]
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```javascript
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let x = 100 / "Apple";
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```
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**Property summary table** [S1]
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| Property | Description |
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|----------|-------------|
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| `Number.EPSILON` | The difference between 1 and the smallest floating-point number greater than 1 |
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| `Number.MAX_VALUE` | The largest possible number in JavaScript |
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| `Number.MIN_VALUE` | The lowest possible number in JavaScript |
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| `Number.MAX_SAFE_INTEGER` | The maximum safe integer (`2⁵³ − 1`) |
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| `Number.MIN_SAFE_INTEGER` | The minimum safe integer (`−(2⁵³ − 1)`) |
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| `Number.POSITIVE_INFINITY` | Returned on overflow (e.g. `1 / 0`) |
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| `Number.NEGATIVE_INFINITY` | Returned on negative overflow (e.g. `-1 / 0`) |
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| `Number.NaN` | Not a Number (e.g. `100 / "Apple"`) |
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## 🛠️ 적용 사례 (Applied in summary)
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The page's own snippets are the canonical applied examples — accessing each constant via `Number.*` and demonstrating overflow (`1 / 0`) and invalid arithmetic (`100 / "Apple"`). No external project/commit applications found in the source.
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## 💻 코드 패턴 (Code patterns)
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Access a static Number property (language: JavaScript):
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```javascript
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let x = Number.MAX_VALUE;
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let y = Number.MAX_SAFE_INTEGER;
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```
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Trigger Infinity through overflow:
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```javascript
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let x = 1 / 0;
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let y = -1 / 0;
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```
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Produce NaN through invalid arithmetic:
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```javascript
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let x = 100 / "Apple";
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```
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## ⚖️ 모순 및 업데이트 (Contradictions & updates)
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No contradictions found in the source.
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## ✅ 검증 상태 및 신뢰도
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- **상태:** draft
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- **검증 단계:** conceptual (실제 적용 사례 발견 시 applied/validated로 승격 가능)
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- **출처 신뢰도:** B (W3Schools — widely used educational reference, not a primary standards body)
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- **신뢰 점수:** 0.88
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- **중복 검사 결과:** 신규 생성 (New discovery)
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## 🔗 지식 그래프 (Knowledge Graph)
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- **상위/루트:** [[JavaScript Tutorial]]
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- **관련 개념:** [[JavaScript Numbers]], [[JavaScript Number Methods]], [[JavaScript BigInt]], [[JavaScript Bitwise]]
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- **참조 맥락:** Referenced when checking numeric limits, detecting overflow, or guarding against unsafe integers.
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## 📚 출처 (Sources)
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- [S1] W3Schools — JavaScript Number Properties — https://www.w3schools.com/js/js_number_properties.asp
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## 📝 변경 이력 (Change history)
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- 2026-06-23: Initial draft synthesized from the W3Schools "JavaScript Number Properties" page (Astra wiki-curation, P-Reinforce v3.1 format).
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