➕void

JS ⟩ statement ⟩ expression ⟩ operator ⟩ unary ⟩ void

(operator)

evaluates its operand, then discards the value and returns undefined.

// ⭐ syntax: void <expr>
const count = () => void counter++;    // ⭐ void: discard return value

💈範例

• void (replit)

let counter = 0;

// ⭐ void: discard return value
const count = () => void counter++;
const count2 = () => { counter++ };    // same as above

count(),    // undefined
counter,    // 1

count2(),   // undefined
counter++,  // 2

📗 參考

• JS 冷知識：你所不知道的 void

• JavaScript: The Definitive Guide ⟩ 4.13.6 The void Operator

📘 手冊

• void operator void expr or void(expr) evaluates the given expr and then returns undefined.

👥 相關

• some transpilers turn undefined into void 0.