2nd/10_Wiki/Topic_JavaScript/JavaScript_Loop_While.md

id, title, category, status, verification_status, canonical_id, aliases, duplicate_of, source_trust_level, confidence_score, created_at, updated_at, review_reason, merge_history, tags, raw_sources, applied_in, github_commit

id	title	category	status	verification_status	canonical_id	aliases	duplicate_of	source_trust_level	confidence_score	created_at	updated_at	review_reason	merge_history	tags	raw_sources	applied_in	github_commit
javascript-while-loop	JavaScript While Loop	Frontend	draft	conceptual		while loop do while JS while loop condition loop do while loop		B	0.89	2026-06-23	2026-06-23			javascript js web frontend w3schools while-loop do-while loops iteration	https://www.w3schools.com/js/js_loop_while.asp

JavaScript While Loop

🎯 한 줄 통찰 (One-line insight)

A while loop runs a block of code as long as a condition is true; its do/while variant guarantees the block runs at least once before the condition is checked. [S1]

🧠 핵심 개념 (Core concepts)

• Condition-driven repetition — the while loop loops through a block of code as long as a specified condition is true. [S1]
• Two while forms — JavaScript offers the while loop and the do/while loop. [S1]
• do/while runs once first — it executes the code block once before checking the condition, then repeats while the condition is true. [S1]
• Runs at least once — do/while runs at least once, even if the condition is false from the start. [S1]
• Infinite-loop hazard — forgetting to increase the condition variable means the loop never ends and crashes the browser. [S1]

🧩 추출된 패턴 (Extracted patterns)

• Advance the counter inside the body — increment the loop variable (i++) within the block so the condition eventually fails. [S1]
• Truthy-element traversal — loop while cars[i] is truthy to walk an array until it runs out of elements. [S1]
• for ↔ while equivalence — a for (;cars[i];) loop and a while (cars[i]) loop express the same iteration. [S1]

📖 세부 내용 (Details)

Introduction [S1] While loops execute a block of code as long as a specified condition is true. JavaScript offers two while loop types: the while loop and the do/while loop.

The while loop [S1] The while loop loops through a block of code as long as a specified condition is true.

while (condition) {
  // code block to be executed
}

while (i < 10) {
  text += "The number is " + i;
  i++;
}

Warning: If you forget to increase the variable used in the condition, the loop will never end. This will crash your browser.

The do/while loop [S1] The do/while loop is a variant of the while loop. This loop will execute the code block once, before checking if the condition is true, then it will repeat the loop as long as the condition is true.

do {
  // code block to be executed
}
while (condition);

do {
  text += "The number is " + i;
  i++;
}
while (i < 10);

The do while runs at least once, even if the condition is false from the start.

Comparing for and while [S1] Using a for loop to traverse a cars array:

const cars = ["BMW", "Volvo", "Saab", "Ford"];
let i = 0;
let text = "";

for (;cars[i];) {
  text += cars[i];
  i++;
}

The same loop expressed as a while loop:

const cars = ["BMW", "Volvo", "Saab", "Ford"];
let i = 0;
let text = "";

while (cars[i]) {
  text += cars[i];
  i++;
}

🛠️ 적용 사례 (Applied in summary)

The page's own snippets are the canonical applied examples — accumulating numbers while i < 10 in both while and do/while forms, and traversing a cars array while cars[i] is truthy. No external project/commit applications found in the source.

💻 코드 패턴 (Code patterns)

Standard while loop:

while (i < 10) {
  text += "The number is " + i;
  i++;
}

Do-while (runs at least once):

do {
  text += "The number is " + i;
  i++;
}
while (i < 10);

Truthy-element array traversal:

while (cars[i]) {
  text += cars[i];
  i++;
}

⚖️ 비교 및 선택 기준 (Comparison & decision criteria)

• while vs do/while — use do/while when the block must run at least once regardless of the initial condition; use while when the block should be skipped entirely if the condition is false at the start. [S1]
• for vs while — the two are interchangeable for condition-only iteration (for (;cars[i];) equals while (cars[i])); choose based on whether you want the init/update folded into the header. [S1]

⚖️ 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: 0.89
• 중복 검사 결과: 신규 생성 (New discovery)

🔗 지식 그래프 (Knowledge Graph)

• 상위/루트: JavaScript Tutorial
• 관련 개념: JavaScript Loops, JavaScript For Loop, JavaScript Break, JavaScript Booleans
• 참조 맥락: The condition-driven iteration construct; companion to the counted JavaScript For Loop.

📚 출처 (Sources)

• [S1] W3Schools — JavaScript While Loop — https://www.w3schools.com/js/js_loop_while.asp

📝 변경 이력 (Change history)

• 2026-06-23: Initial draft synthesized from the W3Schools "JavaScript While Loop" page (Astra wiki-curation, P-Reinforce v3.1 format).