js数据类型symbol

Symbol is a primitive data type in JavaScript. It was introduced in ECMAScript 6 (ES6) and is used to create unique identifiers.

Symbols are unique and immutable, meaning that once created, their value cannot be changed. They are often used as property keys in objects to avoid naming conflicts.

To create a symbol, you can use the Symbol() function. For example:

const mySymbol = Symbol();

You can also provide an optional description as an argument to Symbol() for debugging purposes:

const mySymbol = Symbol('This is a symbol');

Symbols cannot be compared with other data types using equality operators (== and ===). Each symbol is unique, even if they have the same description.

Symbols have several built-in methods and properties, such as Symbol.for() and Symbol.keyFor(), which allow you to create and retrieve global symbols.