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>

10_Wiki/Topic_JavaScript/JavaScript_Iterables.md

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+---
+id: javascript-iterables
+title: "JavaScript Iterables"
+category: "Frontend"
+status: "draft"
+verification_status: "conceptual"
+canonical_id: ""
+aliases: ["JS iterables", "iterable protocol", "for...of", "Symbol.iterator", "iterable objects"]
+duplicate_of: ""
+source_trust_level: "B"
+confidence_score: 0.88
+created_at: 2026-06-23
+updated_at: 2026-06-23
+review_reason: ""
+merge_history: []
+tags: ["javascript", "js", "web", "frontend", "w3schools", "iterables", "for-of", "symbol-iterator"]
+raw_sources: ["https://www.w3schools.com/js/js_iterables.asp"]
+applied_in: []
+github_commit: ""
+---
+
+# [[JavaScript Iterables]]
+
+## 🎯 한 줄 통찰 (One-line insight)
+Iterables are objects that can be looped over with the `for...of` statement; in JavaScript, Strings, Arrays, Typed Arrays, Sets, and Maps are all iterable because their prototypes carry a `Symbol.iterator` method. [S1]
+
+## 🧠 핵심 개념 (Core concepts)
+- **Iterable = loopable with `for...of`** — an iterable is an object that can be iterated (looped) over with the `for...of` statement. [S1]
+- **Built-in iterables** — in JavaScript the following are iterables: Strings, Arrays, Typed Arrays, Sets, and Maps, because their prototypes have a `Symbol.iterator` method. [S1]
+- **The iterator protocol** — an object becomes an iterator by implementing a `next()` method that returns an object with `value` (the next value) and `done` (a boolean indicating completion). [S1]
+- **`Symbol.iterator` is the hook** — an object is made iterable by defining a `Symbol.iterator` method that returns an iterator. [S1]
+
+## 🧩 추출된 패턴 (Extracted patterns)
+- **`for...of` over any iterable** — the same `for (variable of iterable)` loop works uniformly across strings, arrays, sets, and maps. [S1]
+- **Custom iterable via `Symbol.iterator`** — attach a `Symbol.iterator` function to a plain object so it can be used in `for...of`, giving you custom iteration logic for your own data structures. [S1]
+
+## 📖 세부 내용 (Details)
+**Iterables**
+Iterables are iterable objects (like Arrays). Iterables can be accessed with simple and efficient code. Iterables can be iterated over with `for...of` loops. [S1]
+
+**The `for...of` Loop**
+The `for...of` statement loops through the elements of an iterable object. Its syntax is: [S1]
+```javascript
+for (variable of iterable) {
+  // code block to be executed
+}
+```
+
+**Iterating over a String**
+You can use a `for...of` loop to iterate over the elements of a string: [S1]
+```javascript
+const name = "W3Schools";
+
+for (const x of name) {
+  // code block to be executed
+}
+```
+
+**Iterating over an Array**
+You can use a `for...of` loop to iterate over the elements of an array: [S1]
+```javascript
+const letters = ["a","b","c"];
+
+for (const x of letters) {
+  // code block to be executed
+}
+```
+
+**Iterating over Sets and Maps**
+`for...of` can also iterate over the elements of a Set and over the key/value pairs of a Map. [S1]
+
+**JavaScript Iterators**
+The `for...of` loop relies on an iterator. The iterable must implement a method named `Symbol.iterator`. The `Symbol.iterator` method is called automatically by `for...of`. It returns an iterator object with a `next()` method. The `next()` method returns an object with a `value` property (the next value) and a `done` property (`true` or `false`). [S1]
+
+**Built-in Iterables**
+In JavaScript the following are iterables: Strings, Arrays, Typed Arrays, Sets, and Maps. They are iterable because their prototype objects all have a `Symbol.iterator` method. [S1]
+
+**A User-Defined (Home-Made) Iterable**
+You can make an object iterable by giving it a `Symbol.iterator` method. The example below creates an object that returns values 10, 20, 30, 40 ... and stops at 100: [S1]
+```javascript
+myNumbers = {};
+
+myNumbers[Symbol.iterator] = function() {
+  let n = 0;
+  done = false;
+  return {
+    next() {
+      n += 10;
+      if (n == 100) {done = true}
+      return {value:n, done:done};
+    }
+  };
+}
+
+for (const num of myNumbers) {
+  // Any Code Here
+}
+```
+The `next()` method returns an object with two properties: `value` (the next value) and `done` (`true` when iteration is finished). [S1]
+
+## 🛠️ 적용 사례 (Applied in summary)
+The page's own snippets are the canonical applied examples — looping over the string `"W3Schools"`, the array `["a","b","c"]`, and the home-made `myNumbers` iterable built with `Symbol.iterator`. No external project/commit applications found in the source.
+
+## 💻 코드 패턴 (Code patterns)
+Loop over any iterable (language: JavaScript):
+```javascript
+for (const x of "W3Schools") {
+  // code block to be executed
+}
+```
+Make a plain object iterable:
+```javascript
+myNumbers[Symbol.iterator] = function() {
+  let n = 0;
+  done = false;
+  return {
+    next() {
+      n += 10;
+      if (n == 100) {done = true}
+      return {value:n, done:done};
+    }
+  };
+}
+```
+
+## ⚖️ 모순 및 업데이트 (Contradictions & updates)
+No contradictions found in the source.
+
+## ✅ 검증 상태 및 신뢰도
+- **상태:** draft
+- **검증 단계:** conceptual (실제 적용 사례 발견 시 applied/validated로 승격 가능)
+- **출처 신뢰도:** B (W3Schools — widely used educational reference, not a primary standards body)
+- **신뢰 점수:** 0.88
+- **중복 검사 결과:** 신규 생성 (New discovery)
+
+## 🔗 지식 그래프 (Knowledge Graph)
+- **상위/루트:** [[JavaScript Tutorial]]
+- **관련 개념:** [[JavaScript Iterators]], [[JavaScript Generators]], [[JavaScript Symbols]]
+- **참조 맥락:** Referenced whenever using `for...of` loops or building custom data structures that should be loopable.
+
+## 📚 출처 (Sources)
+- [S1] W3Schools — JavaScript Iterables — https://www.w3schools.com/js/js_iterables.asp
+
+## 📝 변경 이력 (Change history)
+- 2026-06-23: Initial draft synthesized from the W3Schools "JavaScript Iterables" page (Astra wiki-curation, P-Reinforce v3.1 format).