4 ms·

Huh? If the runtime can guarantee your function receives an instance of a particular class, that's a lot of boiler plate you don't need to write yourself to as

Huh? If the runtime can guarantee your function receives an instance of a particular class, that's a lot of boiler plate you don't need to write yourself to assert the same thing.

arcticbull 8y ago
Typechecking at the runtime level means that you have to write tests that traverse every single code path to make sure your code works the way you expect. You can just do this at compile time with static typing. Saves you a lot of boiler plate tests you don't need to write yourself to assert the same thing.
- stephenr 8y ago
  In the context of JS 'compile time' refers to.. TS? My point was that if your TS project is used in a non-TS context (i.e. the compiled JS is called from regular JS code, not compiled TS code, you no longer have that compile step. I also think you've misunderstood what I mean. I'm talking about native language level support for typed function arguments at the javascript level, not relying on TS to provide that.
- int_19h 8y ago
  This is where terminology fails us. I really wish the terms "static typing" and "dynamic typing" as presently used would be gone entirely. What you're saying is that explicit type annotations can be enforced at compile time. However, they can also be enforced at runtime, and they're no less safe for that - you just see the errors later, but any call that would be blocked by a static type checker can similarly be blocked by a dynamic checker. I think that's what OP refers to by "runtime checking", not writing explicit asserts.
  - stephenr 8y ago
    Thankyou, im glad someone understood the point. A similar example that web-focused developers are likely familiar with, is type hinting in PHP. For the developer's purpose, there is no 'compile' step (yes the code is compiled and then run, but it happens at request time so its not realistic to compare it to compile time type checking in a compile language like Java). The 'compile/run' lifetime (in browser based JS) bears similarity to that of PHP: compile time effectively is run time, because it's compiled during the request and then executed immediately.
    - arcticbull 8y ago
      100% it's just as safe, though I doubt the program is more reliable as it's harder to catch issues later on.

Huh? If the runtime can guarantee your function receives an instance of a particular class, that's a lot of boiler plate you don't need to write yourself to assert the same thing.

arcticbull 8y ago

Typechecking at the runtime level means that you have to write tests that traverse every single code path to make sure your code works the way you expect. You can just do this at compile time with static typing. Saves you a lot of boiler plate tests you don't need to write yourself to assert the same thing.

stephenr 8y ago
In the context of JS 'compile time' refers to.. TS? My point was that if your TS project is used in a non-TS context (i.e. the compiled JS is called from regular JS code, not compiled TS code, you no longer have that compile step. I also think you've misunderstood what I mean. I'm talking about native language level support for typed function arguments at the javascript level, not relying on TS to provide that.
int_19h 8y ago
This is where terminology fails us. I really wish the terms "static typing" and "dynamic typing" as presently used would be gone entirely. What you're saying is that explicit type annotations can be enforced at compile time. However, they can also be enforced at runtime, and they're no less safe for that - you just see the errors later, but any call that would be blocked by a static type checker can similarly be blocked by a dynamic checker. I think that's what OP refers to by "runtime checking", not writing explicit asserts.
- stephenr 8y ago
  Thankyou, im glad someone understood the point. A similar example that web-focused developers are likely familiar with, is type hinting in PHP. For the developer's purpose, there is no 'compile' step (yes the code is compiled and then run, but it happens at request time so its not realistic to compare it to compile time type checking in a compile language like Java). The 'compile/run' lifetime (in browser based JS) bears similarity to that of PHP: compile time effectively is run time, because it's compiled during the request and then executed immediately.
  - arcticbull 8y ago
    100% it's just as safe, though I doubt the program is more reliable as it's harder to catch issues later on.