ES6 data type

1. Basic data types (6 types)

type of data	From the ES version	typeof
null	ES5	Object
undefined	ES5	undefined
boolean	ES5	boolean
number	ES5	number
string	ES5	string
symbol	ES6	symbol

2. Reference data type (2 types)

type of data	From the ES version	typeof
object	ES5	object
function	ES5	function

3. Access, modify and copy

• Basic data types: save values ​​in the stack and access by value. The operation is their actual value, and the different variables do not interfere with each other.
• Reference data type: save the address in the stack and access by reference. When querying, find the value in the heap memory according to the address; when modifying, multiple variables under shallow copy save the same address, any modification of a variable will change the value under the corresponding address, you can use deep copy to solve this problem.

4. Data type detection

5. Data type conversion