4 ms·

That's already built in to the language: let logNow = log.bind(null, new Date()); // [sic, "now" is fixed] let debugNow = logNow.bind(null, "DEBUG"); Also

That's already built in to the language: let logNow = log.bind(null, new Date()); // [sic, "now" is fixed] let debugNow = logNow.bind(null, "DEBUG"); Also, uglifiers and transpilers do some horrifying stuff, this won't break if fn.length is tempered with. Unlike the article implementation.

masklinn 5y ago
That is not currying, it’s partial application.
- q-rews 5y ago
  Currying makes it implicit, but it's the same thing. const one = curriedSum(1) one(2) is the same as const one = sum.bind(null, 1) one(2) with the exception that the latter is explicit and not as slow as `curriedSum`. Both `sum` and `curriedSum` can be used the same way: curriedSum(1)(2) sum.bind(null, 1)(2) or just: curriedSum(1, 2) sum(1, 2) One of the advantages is that non-curried functions make the return value explicit. You can't implement `sum(...addends)` with currying because curried functions have a fixed number of parameters. Once past that, a call will not return a function anymore. sum.bind(null, 1).bind(null, 2).bind(null, 3).bind(null, 4) // Still not called curriedSum(1)(2)(3)(4) // Maybe it works, maybe undefined is not a function
  - zodiakzz 5y ago
    They're technically correct. And if you gotta write on HN, you better get the terminology correct (and that derails threads into interesting tangents often) so my bad. Gotta say currying seems to be useless in real world. No advantage whatsoever over partial application.
- zodiakzz 5y ago
  Ah, TIL. If we are being pedants. Wikipedia says: > currying is the technique of converting a function that takes multiple arguments into a sequence of functions that each takes a *single argument*. So the article isn't currying either. It's a hybrid between currying and partial application. TBH I can't think of a practical case where you'd prefer currying over partial application. Theory/philosophy aside.
  - masklinn 5y ago
    > So the article isn't currying either. It's a hybrid between currying and partial application. Sure. > TBH I can't think of a practical case where you'd prefer currying over partial application. Theory/philosophy aside. For eager-evaluation uncurried language (like javascript) I would also struggle to think of one. For curried languages, it can sometimes be useful to uncurry functions in order to make types match, after which you might have to curry them back into the "normal" form to use them.
g_b 5y ago
Easier to read version: let logNow = (importance, message) => log(new Date(), importance, message); let debugNow = message => logNow("DEBUG", message); And with this implementation, current IDEs provide a more informative auto-complete.
- zodiakzz 5y ago
  Wrong. Your implementation loses all parameter typing, defaulting to "any". IDEs have correct TS definitions for .bind().

masklinn 5y ago

That is not currying, it’s partial application.

q-rews 5y ago
Currying makes it implicit, but it's the same thing. const one = curriedSum(1) one(2) is the same as const one = sum.bind(null, 1) one(2) with the exception that the latter is explicit and not as slow as `curriedSum`. Both `sum` and `curriedSum` can be used the same way: curriedSum(1)(2) sum.bind(null, 1)(2) or just: curriedSum(1, 2) sum(1, 2) One of the advantages is that non-curried functions make the return value explicit. You can't implement `sum(...addends)` with currying because curried functions have a fixed number of parameters. Once past that, a call will not return a function anymore. sum.bind(null, 1).bind(null, 2).bind(null, 3).bind(null, 4) // Still not called curriedSum(1)(2)(3)(4) // Maybe it works, maybe undefined is not a function
- zodiakzz 5y ago
  They're technically correct. And if you gotta write on HN, you better get the terminology correct (and that derails threads into interesting tangents often) so my bad. Gotta say currying seems to be useless in real world. No advantage whatsoever over partial application.
zodiakzz 5y ago
Ah, TIL. If we are being pedants. Wikipedia says: > currying is the technique of converting a function that takes multiple arguments into a sequence of functions that each takes a *single argument*. So the article isn't currying either. It's a hybrid between currying and partial application. TBH I can't think of a practical case where you'd prefer currying over partial application. Theory/philosophy aside.
- masklinn 5y ago
  > So the article isn't currying either. It's a hybrid between currying and partial application. Sure. > TBH I can't think of a practical case where you'd prefer currying over partial application. Theory/philosophy aside. For eager-evaluation uncurried language (like javascript) I would also struggle to think of one. For curried languages, it can sometimes be useful to uncurry functions in order to make types match, after which you might have to curry them back into the "normal" form to use them.

g_b 5y ago

Easier to read version: let logNow = (importance, message) => log(new Date(), importance, message); let debugNow = message => logNow("DEBUG", message); And with this implementation, current IDEs provide a more informative auto-complete.

zodiakzz 5y ago
Wrong. Your implementation loses all parameter typing, defaulting to "any". IDEs have correct TS definitions for .bind().