2nd/10_Wiki/Dev/Topic_JavaScript/JavaScript_Function_Parameters.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-function-parameters	JavaScript Function Parameters	Frontend	draft	conceptual		function parameters arguments parameters vs arguments default parameters parameter rules function input		B	0.87	2026-06-23	2026-06-23			javascript js web frontend w3schools functions parameters	https://www.w3schools.com/js/js_function_parameters.asp

JavaScript Function Parameters

🎯 한 줄 통찰 (One-line insight)

Parameters are the named inputs a function declares in its parentheses; arguments are the real values passed in when it is called — and JavaScript checks neither their types nor their count. [S1]

🧠 핵심 개념 (Core concepts)

• Parameters pass values in — parameters allow you to send values to a function and are listed inside the parentheses in the function definition. [S1]
• Parameters vs arguments — parameters are the names listed in the function definition; arguments are the real values passed to and received by the function. [S1]
• No type or count enforcement — JavaScript function definitions do not specify data types for parameters, do not perform type checking on arguments, and do not check the number of arguments received. [S1]
• Missing arguments give wrong results — accessing a function with an incorrect (missing) parameter can return an incorrect answer. [S1]
• Default parameter values — ECMAScript 2015 allows function parameters to have default values, used when no argument is provided. [S1]

🧩 추출된 패턴 (Extracted patterns)

• One or many parameters — declare a single parameter, or as many as needed separated by commas. [S1]
• Default fallback — function f(x, y = 10) supplies 10 when the second argument is omitted. [S1]
• No safety net — because there is no type/count checking, a missing argument silently flows through (e.g. toCelsius() with no input). [S1]

📖 세부 내용 (Details)

Parameters (Function Input) — parameters allow you to pass (send) values to a function; they are listed inside the parentheses in the function definition. [S1]

Functions with One Parameter — a function can have one parameter: [S1]

function sayHello(name) {
  return "Hello " + name;
}

let greeting = sayHello("John");

A single-parameter conversion: [S1]

function toCelsius(fahrenheit) {
  return (5 / 9) * (fahrenheit - 32);
}

let value = toCelsius(77);

Functions with Multiple Parameters — you can add as many parameters as you want, separated by commas: [S1]

function multiply(a, b) {
  return a * b;
}

let result = multiply(4, 5);

function fullName(firstName, lastName) {
  return firstName + " " + lastName;
}

let name = fullName("John", "Doe");

Parameters vs. Arguments — parameters are the names listed in the function definition; arguments are the real values passed to and received by the function. [S1]

Parameter Rules — JavaScript function definitions do not specify data types for parameters; JavaScript functions do not perform type checking on the arguments; JavaScript functions do not check the number of arguments received. [S1]

Incorrect Parameters — accessing a function with an incorrect (missing) parameter can return an incorrect answer: [S1]

function toCelsius(fahrenheit) {
  return (5/9) * (fahrenheit-32);
}

let value = toCelsius();

Default Parameter Values — ECMAScript 2015 allows function parameters to have default values; the default value is used if no argument is provided: [S1]

function myFunction(x, y = 10) {
  return x + y;
}
myFunction(5);

🛠️ 적용 사례 (Applied in summary)

The page's own snippets are the canonical applied examples — single-parameter sayHello(name) and toCelsius(fahrenheit), multi-parameter multiply(a, b) and fullName(firstName, lastName), the missing-argument toCelsius() case, and the default-parameter myFunction(x, y = 10). No external project/commit applications found in the source.

💻 코드 패턴 (Code patterns)

Multiple parameters (language: JavaScript):

function fullName(firstName, lastName) {
  return firstName + " " + lastName;
}

let name = fullName("John", "Doe");

Default parameter value:

function myFunction(x, y = 10) {
  return x + y;
}
myFunction(5);

⚖️ 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: 0.87
• 중복 검사 결과: 신규 생성 (New discovery)

🔗 지식 그래프 (Knowledge Graph)

• 상위/루트: JavaScript Tutorial
• 관련 개념: JavaScript Functions, JavaScript Function Definitions, JavaScript Function Invocation, JavaScript Function Returns
• 참조 맥락: Referenced when designing a function's inputs, defaults, and how callers supply arguments.

📚 출처 (Sources)

• [S1] W3Schools — JavaScript Function Parameters — https://www.w3schools.com/js/js_function_parameters.asp

📝 변경 이력 (Change history)

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