Core JavaScript objects

1. array object
An array is a common data structure. It is generally used to store a group of identical objects or data.
Main attributes:

Attribute	Description
Length	Number of elements in the current array
Prototype	Allow additional attributes to be added to an array object

Common Methods:

Method	Description
Concat	Concatenates two arrays and returns a new group.
Join	Combine all elements in the array into a string and return
Pop	Remove a nonprime from the end of the array and return the value of this nonprime.
Push	Press an element to the end of the array.
Reverse	Returns the array in the original order.
Shift	Removes the first element from the array and returns the value of this element.
Slice	Evaluate the sub-array of the array and return this array
Sort	Sorts elements in an array.
Splice	Insert/delete or replace elements in the array
Tostring	Converts an array to a string.
Unshif	Insert an element at the beginning of the array

2. boolean object
A boolean object is a Boolean encapsulation. A boolean object is used to convert a non-Boolean value to a Boolean value. For a non-Boolean value, use the following rules for conversion.
1. All objects are considered true.
2. the string is considered as false only when it is null,
3. null and undefined are considered false.
4. if and only if the value is zero, the value is false.

3. date object
The date object constructor has the following format:
1. New Date ().
2. New date ("Month day, year hours: Minutes: Seconds ")
3. New Date (yr_num, mo_num, day_num)
4. New Date (yr_num, mo_monum, day_num, hr_num, min_num, sec_num)