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_JSON_Parse.md

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+---
+id: json-parse
+title: "JSON Parse"
+category: "Frontend"
+status: "draft"
+verification_status: "conceptual"
+canonical_id: ""
+aliases: ["JSON.parse", "JSON parse", "parse JSON", "JSON to object", "reviver function"]
+duplicate_of: ""
+source_trust_level: "B"
+confidence_score: 0.9
+created_at: 2026-06-23
+updated_at: 2026-06-23
+review_reason: ""
+merge_history: []
+tags: ["javascript", "js", "web", "frontend", "w3schools", "json", "parse"]
+raw_sources: ["https://www.w3schools.com/js/js_json_parse.asp"]
+applied_in: []
+github_commit: ""
+---
+
+# [[JSON Parse]]
+
+## 🎯 한 줄 통찰 (One-line insight)
+When data arrives from a web server it is always a string; `JSON.parse()` turns that JSON string into a usable JavaScript object (or array), and dates and functions — which JSON cannot carry — must be reconstructed by hand or via a reviver. [S1]
+
+## 🧠 핵심 개념 (Core concepts)
+- **Server data is always a string** — a common use of JSON is to exchange data to/from a web server; when receiving it, parse with `JSON.parse()` and the data becomes a JavaScript object. [S1]
+- **Text must be valid JSON** — make sure the text is in JSON format, or you will get a syntax error. [S1]
+- **Arrays parse to arrays** — using `JSON.parse()` on JSON derived from an array returns a JavaScript array, not an object. [S1]
+- **Dates are not allowed in JSON** — store a date as a string, then convert it back to a Date object later (directly or with a reviver function). [S1]
+- **Functions are not allowed in JSON** — avoid them; reconstructing requires `eval()`, and functions lose their scope. [S1]
+
+## 🧩 추출된 패턴 (Extracted patterns)
+- **Receive → parse → render** — `JSON.parse(text)` then read fields into the page. [S1]
+- **Reviver pattern** — pass a function as the second argument to `JSON.parse()` to transform values (e.g. convert a `"birth"` string into a Date) during parsing. [S1]
+- **Manual rehydration** — after parsing, replace a string field with a real object: `obj.birth = new Date(obj.birth)`. [S1]
+
+## 📖 세부 내용 (Details)
+A common use of JSON is to exchange data to/from a web server. When receiving data from a web server, the data is always a string. Parse the data with `JSON.parse()`, and the data becomes a JavaScript object. [S1]
+
+**Example — parsing JSON**
+Imagine we received this text from a web server: `'{"name":"John", "age":30, "city":"New York"}'`. Use `JSON.parse()` to convert the text into a JavaScript object: [S1]
+```javascript
+const obj = JSON.parse('{"name":"John", "age":30, "city":"New York"}');
+```
+Make sure the text is in JSON format, or else you will get a syntax error. Then use the object in your page: [S1]
+```javascript
+<p id="demo"></p>
+<script>
+document.getElementById("demo").innerHTML = obj.name;
+</script>
+```
+
+**Array as JSON**
+When using `JSON.parse()` on a JSON derived from an array, the method will return a JavaScript array, instead of a JavaScript object: [S1]
+```javascript
+const text = '["Ford", "BMW", "Audi", "Fiat"]';
+const myArr = JSON.parse(text);
+```
+
+**Exceptions — parsing dates**
+Date objects are not allowed in JSON. If you need to include a date, write it as a string. You can convert it back into a date object later. Convert directly after parsing: [S1]
+```javascript
+const text = '{"name":"John", "birth":"1986-12-14", "city":"New York"}';
+const obj = JSON.parse(text);
+obj.birth = new Date(obj.birth);
+document.getElementById("demo").innerHTML = obj.name + ", " + obj.birth;
+```
+Or use the second parameter of `JSON.parse()`, called the reviver function, which is called on each value before returning it: [S1]
+```javascript
+const text = '{"name":"John", "birth":"1986-12-14", "city":"New York"}';
+const obj = JSON.parse(text, function (key, value) {
+  if (key == "birth") {
+    return new Date(value);
+  } else {
+    return value;
+  }
+});
+document.getElementById("demo").innerHTML = obj.name + ", " + obj.birth;
+```
+
+**Exceptions — parsing functions**
+Functions are not allowed in JSON. If you need to include a function, write it as a string and convert it back into a function later: [S1]
+```javascript
+const text = '{"name":"John", "age":"function () {return 30;}", "city":"New York"}';
+const obj = JSON.parse(text);
+obj.age = eval("(" + obj.age + ")");
+document.getElementById("demo").innerHTML = obj.name + ", " + obj.age();
+```
+You should avoid using functions in JSON; the functions will lose their scope, and you would have to use `eval()` to convert them back into functions. [S1]
+
+## 🛠️ 적용 사례 (Applied in summary)
+Applied examples on the page: parse server text into `obj` and render `obj.name` into `#demo`; parse a JSON array into a real array; rehydrate a date both manually and via a reviver; and (discouraged) rebuild a function with `eval()`. No external project/commit applications found in the source.
+
+## 💻 코드 패턴 (Code patterns)
+Parse server text into an object:
+```javascript
+const obj = JSON.parse('{"name":"John", "age":30, "city":"New York"}');
+document.getElementById("demo").innerHTML = obj.name;
+```
+Reviver to reconstruct a date during parse:
+```javascript
+const obj = JSON.parse(text, function (key, value) {
+  if (key == "birth") {
+    return new Date(value);
+  } else {
+    return value;
+  }
+});
+```
+
+## ⚖️ 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:** 0.90
+- **중복 검사 결과:** 신규 생성 (New discovery)
+
+## 🔗 지식 그래프 (Knowledge Graph)
+- **상위/루트:** [[JavaScript Tutorial]]
+- **관련 개념:** [[JavaScript JSON Stringify]], [[JavaScript JSON]], [[JavaScript JSON Data Types]], [[JavaScript JSON Objects]]
+- **참조 맥락:** Referenced whenever consuming JSON received from a server or storage and turning it into usable objects.
+
+## 📚 출처 (Sources)
+- [S1] W3Schools — JSON Parse — https://www.w3schools.com/js/js_json_parse.asp
+
+## 📝 변경 이력 (Change history)
+- 2026-06-23: Initial draft synthesized from the W3Schools "JSON Parse" page (Astra wiki-curation, P-Reinforce v3.1 format).