Enumerability and ownership of properties

原文:

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Enumerability_and_ownership_of_properties

Enumerable properties whose internal enumerable flag is set to true

enumerable flag 是 預設給 透過 simple assignment 或是 property initializer 所做出來的 properties

Enumerable properties show up (出現 ?) 在 for...in loops unless the properties's key is a symbol.

意思是: if..not 替換 unless ，假若 properties的key不是一個symbol，這個key就會出現在 for...in loop裏頭。

MDN文件

CodeCademy 提及MDN文件:

Practice your documentation reading skills and check out: MDN’s object instance documentation.

To read more about either arrow functions or the global object check out the MDN documentation of the global object and arrow functions.