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1) Many languages won't allow you to redefine a type. 2) Mutate the prototype of a "frozen" object and you would indirectly affect it through its prototype cha

1) Many languages won't allow you to redefine a type. 2) Mutate the prototype of a "frozen" object and you would indirectly affect it through its prototype chain... or mutate an nested property inside a "frozen" object. Most of JS standard library and most popular frameworks and libraries have fully mutable definitions. That sucks and is BAD design decision.

alephnan 8y ago
> Many languages won't allow you to redefine a type. This counterargument is not a good one. Just because other languages do things a certain way doesn't mean it's the right way in every situation. C++ has multiple inheritances and template metaprogramming, but that's C++. > Most of JS standard library and most popular frameworks and libraries have fully mutable definitions. That sucks and is BAD design decision. It's subjective whether this is a bad design decision. For the standard library, this enables polyfills. As for the popular libraries / frameworks, they have the option of freezing the prototype. They don't do this because they make the fair assumption that the client is not mutating the library state. It's the programmer's fault for breaking the interface contract and mutating the implementation. At any rate, this would be a criticism of the ecosystem, rather than language. If the criticism is about untrusted third party code, it's not an apples-to-apples comparison between JavaScript and other languages that are operating in different environments.
- partycoder 8y ago
  1) Template meta-programming is vastly safer than preprocessor macros. Then, today you have constant expressions, which overlap with some of the use-cases of template meta-programming. In any case, template meta-programming is not strictly required to get things done in C++. Multiple inheritance can be caught by static analysis. 2) Just like you can polyfill your code, malicious input can poison your prototypes.

alephnan 8y ago

> Many languages won't allow you to redefine a type. This counterargument is not a good one. Just because other languages do things a certain way doesn't mean it's the right way in every situation. C++ has multiple inheritances and template metaprogramming, but that's C++. > Most of JS standard library and most popular frameworks and libraries have fully mutable definitions. That sucks and is BAD design decision. It's subjective whether this is a bad design decision. For the standard library, this enables polyfills. As for the popular libraries / frameworks, they have the option of freezing the prototype. They don't do this because they make the fair assumption that the client is not mutating the library state. It's the programmer's fault for breaking the interface contract and mutating the implementation. At any rate, this would be a criticism of the ecosystem, rather than language. If the criticism is about untrusted third party code, it's not an apples-to-apples comparison between JavaScript and other languages that are operating in different environments.

partycoder 8y ago
1) Template meta-programming is vastly safer than preprocessor macros. Then, today you have constant expressions, which overlap with some of the use-cases of template meta-programming. In any case, template meta-programming is not strictly required to get things done in C++. Multiple inheritance can be caught by static analysis. 2) Just like you can polyfill your code, malicious input can poison your prototypes.