How to Properly Extend Object.prototype in JavaScript for Library Users

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Understanding Prototype Extension in JavaScript

The Problem

Imagine you want your library users to be able to utilize a new method called greet on all objects. Your initial attempt might look like this:

[[See Video to Reveal this Text or Code Snippet]]

But how can you ensure that library users can call this method just like they would with ({}).greet()?

The Misstep

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Why This Doesn’t Work

Legacy Objects: If overwriting were possible, only new objects would have access to the new methods. Existing objects wouldn't.

Losing Default Functions: Replace the prototype, and you'd lose the default methods of JavaScript objects, which are non-enumerable and wouldn't be copied over.

Strict Mode Errors: If you were in strict mode, this operation would throw a TypeError, alerting you that you're trying to assign a read-only property.

The Solution

1. Direct Assignment

You can add methods directly to the prototype like this:

[[See Video to Reveal this Text or Code Snippet]]

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

Remember, always consider using strict mode in your code to catch common mistakes early on. Happy coding!