Currying in JavaScript

Let's look at a few examples of Currying in JavaScript

[ivanvolti]

Thanks for the video. BTW, I think the main thing here is partial application (PA). And currying just gives you automatic (implicit) partial application.

Manual PA: `numbers.map(num => add(2, num))` or `numbers.map(add.bind(null, 2))`
Automatic PA: `numbers.map(add(2))` -- With currying you effortlessly create specialized unary functions on the fly with very little code using a “point-free” style.

Automatic partial application reduces boilerplate code and gives you complete control over when and how evaluation takes place. You can call a curried function all at once or prepare it first by pre-loading it with some "settings" and later operate on data getting the value.

So if you do a lot of partial application, currying is your friend. Otherwise, you probably don't need currying at all. Also, currying is not free: for instance, it can add significantly to the stack trace making your debugging experience worse.

[DivineSoB]

Currying has always been tricky. Thank you for the video. That and 'this' binding and prototype inheritance made me cry internally the first time I had to implement them.

[kts]

The first example was the exact same question I was asked for an interview for a company. Even the arguments were the same (2, 3). It can be one lined: const c = (a, b) => b ? a + b : (y) => a + y;

[krasenoo]

I found a pretty nice use case for currying back when I was writing Angular 1.x. I used to pass partially applied functions to child components instead of signaling events.

[TheEvilSoft]

I would say that the code submitted is in fact currying, just not auto curried, you have to `fname (a) (b) (c) (d, e)`

[TheEvilSoft]

Great Screencast! Even though I am a functional JS programmer and typically lean to a declarative style, if I am on a project or submitting things in OS, unless the project has a sense of declarative FP then it is bad news bears to create a cognitive speed bump by switching it all up, IMO. Not fair to the other members of the team/project. Unless there is a specific desire to away from an imperative approach. I love how you communicated that point. Now lets see about getting you more acquainted to the beautiful world of declarative functional JavaScript.

[markwillis]

Understands currying... can't add 2 + 3. Developer brains. 😀

Kidding by the way, this was SUCH a great video. I'm refactoring some functions that use currying and had to get my head around it, this video has pretty much unlocked the answer. I think.
I'm yet to find a useless KCD video...

[mrchedda]

Am I crazy or does currying sorta sound similar to recursion? 🤷🏽‍♂️

[omgdd]

I tend to prefer currying for generic utilities (lodash/fp, ramda) and PA the closer I get to app specific code. I like to write PA functions when I want to isolate some state to the bits of code that need it vs bloating a calling function, or as a means of dependency injection. I've found it extremely helpful for keeping functions small and focused, but I'll admit it takes some getting used to.

[waldothedev]

So to do my mental study notes: Currying is a function that returns another function if it hasn't received all the arguments that it needs yet.... (7:51)

[pantherfanatic]

Nice video! Can't believe that idiot thought he was currying. Shouldn't even be a developer, imo