➕new

creating objects using `new F()` syntax.

JS ⟩ value ⟩ object ⟩ create ⟩ new

(operator) (🌟 table of operators)

create objects by using constructor functions. (👉 callable vs. constructable)

new Object() 
new Point(2,3)

new Object        // empty pair of parentheses can be omitted
new Date

🈯 synonyms： "object creation expression"

🧨 雷區

class can only be instantiated with the new operator — attempting to call a class without new will throw a TypeError❗

⭐️ 重點

objects created by new F() use F.prototype as their prototype.

a function can know whether it is invoked with new by checking new.target. new.target is only undefined when the function is invoked without new.

👥 相關

• callable vs. constructable

• new.target

📗 參考

• JavaScript: The Definitive Guide ⟩

  • 4.6 Object Creation Expressions

  • Ch. 9 Classes

📘 手冊

• new