🔰lexical environment

JS ⟩ concept ⟩ execution context ⟩ lexical environment

In JavaScript, every running function, code block {...}, and the script as a whole have an internal associated object known as the "lexical environment", it consists of two parts:

• environment record – an object that stores

  • all local variable(s) as its properties.

  • other information like the value of this.

• A reference to the outer lexical environment (associated with the outer code).

📗 JS.info ⟩ Lexical Environment

🖥️ 影片

• replit：lexical environment - Counter()

// make counter
function Counter() {

    let count = 0;

    return function() {
        return ++count;
    };
}

// a counter instance
let counter = Counter();

counter(),    // 1
counter(),    // 2

🔴 主題

🗺️ 圖解

⭐️ 重點

👥 相關

📗 參考

📘 手冊

🗣 討論

❓