6 ms·

Iterators and callbacks aren’t comparable. You don’t use them for the same thing.

BiteCode_dev 7y ago
What do you think each(), map() and filter() do ? But even without that, I'm not saying they are comparable. I'm saying the same API will use explicit anonymous callbacks in JS and something else in Python (decorators, subclassing, protocols, generators...). I'm saying that the same API will use __iter__ in Python and something else in JS (type conversion, proxy object, explicit method call...). E.G, this is a Python pattern you'll find in contextlib or in pytest fixtures: @somekindofregistration def foo(): print('code that runs before') try: yield except Stuff: print('Error handling') print('code that runs after') This uses Python iteration mechanism to run code at 3 different times in a life cycle. While in JS, you would pass 3 callbacks.
- WoodTree 7y ago
  Map, filter, and fold are higher order functions, functions which take functions as parameters. You are misusing the word callback. A callback is a function passed to another thread that will maybe be invoked later as a response (like it calls you back).
  - BiteCode_dev 7y ago
    https://en.m.wikipedia.org/wiki/Callback_(computer_programming) https://en.m.wikipedia.org/wiki/Callback_(computer_programmi...
  - zbentley 7y ago
    That's not what a callback is. A callback is just a function passed to an outer function that the outer function may call. Even MDN uses the term callback to describe e.g. the argument to 'map': https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe... In contrast, Lodash goes out of its way not to use the term "callback", presumably to avoid confusion since it's a place where many functions-that-take-a-function-argument do not call the provided function, e.g. https://lodash.com/docs/#curry https://lodash.com/docs/#curry

What do you think each(), map() and filter() do ? But even without that, I'm not saying they are comparable. I'm saying the same API will use explicit anonymous callbacks in JS and something else in Python (decorators, subclassing, protocols, generators...). I'm saying that the same API will use __iter__ in Python and something else in JS (type conversion, proxy object, explicit method call...). E.G, this is a Python pattern you'll find in contextlib or in pytest fixtures: @somekindofregistration def foo(): print('code that runs before') try: yield except Stuff: print('Error handling') print('code that runs after') This uses Python iteration mechanism to run code at 3 different times in a life cycle. While in JS, you would pass 3 callbacks.

WoodTree 7y ago
Map, filter, and fold are higher order functions, functions which take functions as parameters. You are misusing the word callback. A callback is a function passed to another thread that will maybe be invoked later as a response (like it calls you back).
- BiteCode_dev 7y ago
  https://en.m.wikipedia.org/wiki/Callback_(computer_programming) https://en.m.wikipedia.org/wiki/Callback_(computer_programmi...
- zbentley 7y ago
  That's not what a callback is. A callback is just a function passed to an outer function that the outer function may call. Even MDN uses the term callback to describe e.g. the argument to 'map': https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe... In contrast, Lodash goes out of its way not to use the term "callback", presumably to avoid confusion since it's a place where many functions-that-take-a-function-argument do not call the provided function, e.g. https://lodash.com/docs/#curry https://lodash.com/docs/#curry