The closure in JS

The characteristics of a closed package

1. Function Nesting function

2. External parameters and variables can be referenced inside the function

3. Parameters and variables are not recycled by the garbage collection mechanism

Second, the definition of closure and its advantages and disadvantages

Official definition: Closures refer to functions that have access to another function scope, and the most common way to create closures is to create another function in one function and access the local variables of the function through another function.

Self-understanding: The closure is the function inside the nested function, the inside function can access the variables outside the function (scope chain)

Closure disadvantage: Resident memory, increased memory usage, resulting in memory leaks

Closure Application Purpose: In order to design private methods and variables

Iii. closure of nested functions

The closure in JS