Why Should You Avoid Global Variables in JavaScript?

Why Should Global Variables Be Avoided in JavaScript?

Contrary to popular belief, cluttering the global namespace is not the sole reason why global variables are discouraged in JavaScript.

Reduced Performance

Global variables require more processing time compared to local variables. This is because JavaScript has to search the entire global scope to locate a global variable, adding a small but noticeable delay.

Namespace Pollution

While grouping global variables within an object can mitigate the namespace issue, it still introduces a level of complexity and potential conflicts with other libraries or scripts.

Accidental Overwrites and Undesired Declarations

Declaring variables as global can lead to accidental overwrites or re-declarations. If a local variable with the same name is created later, it will unintentionally overwrite the global counterpart.

Best Practices

To maintain code integrity and performance, it's recommended to keep global variables to a minimum. Instead, utilize local variables within functions and modules, and avoid using global scope whenever possible.

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