What problems can js closures solve?

Closure means that in JavaScript, internal functions can access variables in the scope of external functions and can maintain references to these variables. It can solve the problem of "encapsulating variables", "maintaining variable status", and " Modular Development", "Callback Functions" and "Problems in Loops" are common issues.

# Operating system for this tutorial: Windows 10 system, Dell G3 computer.

Closure means that in JavaScript, internal functions can access variables in the scope of external functions and can maintain references to these variables even if the external function has ended execution. Closures can solve some of the following common problems:

1. Encapsulation variables: Through closures, private variables and functions can be created to achieve encapsulation, avoid global naming conflicts, and control access permissions.

2. Maintain variable state: Use closures to maintain references to local variables after the external function completes execution, thereby maintaining the state of the variable, such as counters and other functions.

3. Modular development: Closures can be used to implement modular development, encapsulating related variables and functions inside the closure, reducing the pollution of global variables and improving code maintainability.

4. Callback function: In asynchronous programming, closures are often used to save context information in callback functions to ensure that the callback function can access the correct variables.

5. Solve problems in loops: Creating closures in loops can solve variable sharing problems that may be caused by asynchronous operations in traditional loops.

Although closures can solve the above problems, excessive use of closures may also lead to memory leaks and other problems. Therefore, when using closures, you need to pay attention to reasonable use and release them in time when they are no longer needed. of memory.

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