What about javascript closures

Javascript closure is a very useful feature. It can access a function of a variable in the scope of another function, so that the variables in the function can be protected and will not be modified by external functions. The advantages of JavaScript closures include reading variables inside functions, maintaining data persistence, creating function factories and dynamic functions, encapsulating and hiding data; disadvantages include resident memory and changing the values ​​of variables inside parent functions. Therefore, you need to pay attention when using it: avoid abusing closures, use memory-intensive operations with caution, and be careful to avoid modifying variables of external functions.

The operating system of this tutorial: windows10 system, ECMAScript 2023 version, Dell G3 computer.

JavaScript closure is a very useful feature that allows a function to access variables in the scope of another function, so that the variables in the function can be protected from being modified by external functions.

Advantages:

1. Read variables inside the function: Closures can access variables inside the function, even if the function has completed execution.
2. Maintain data persistence: Closures can continue to access the variables of the external function, even if the external function has completed execution. This is useful for scenarios where you need to maintain data state or extend the lifetime of a variable.
3. Create function factories and dynamic functions: Functions can be dynamically generated through closures, and each function has its own independent scope and state. This allows you to create a function factory that generates different functions based on different parameters.
4. Encapsulating and hiding data: Private variables can be created through closures, which can only be accessed and modified in internal functions and cannot be directly accessed from the outside. This can encapsulate and hide data details and improve code security.

Disadvantages:

1. Resident memory: Since closures will cause the variables in the function to be stored in memory, the memory consumption is very large, so closures cannot be abused. , otherwise it will cause performance problems on the web page and may cause memory leaks in IE.
2. Change the value of the variable inside the parent function: The closure will change the value of the variable inside the parent function outside the parent function.

Therefore, you need to pay attention to the following points when using JavaScript closures: avoid abusing closures, use memory-intensive operations with caution, and be careful to avoid modifying variables of external functions. At the same time, you need to decide whether to use closures based on specific application scenarios.

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