ramda.js

问题 I am currently learning functional programming using HyperappJS (V2) and RamdaJS. My first project is a simple blog app where users can comment on posts or other comments. The comments are represented as a tree structure. My state looks something like this: // state.js export default { posts: [ { topic: `Topic A`, comments: [] }, { topic: `Topic B`, comments: [ { text: `Comment`, comments: [ /* ... */ ] } ] }, { topic: `Topic C`, comments: [] } ], otherstuff: ... } When the user wants to add

问题 I am learning monads and doing my first "login" case. The steps are simple: User input userName and password; From database, get user by userName, and get its password saved in database; compare the input password with the one in the database. From the above, there is a requirements to fork 2 monads and merge them to compare. I read nearly all javascripts FP books and monads implementations I can think of, but still cannot found any solutions. The below is what I got so far, it works, but it

问题 I am learning monads and doing my first "login" case. The steps are simple: User input userName and password; From database, get user by userName, and get its password saved in database; compare the input password with the one in the database. From the above, there is a requirements to fork 2 monads and merge them to compare. I read nearly all javascripts FP books and monads implementations I can think of, but still cannot found any solutions. The below is what I got so far, it works, but it

问题 I'm building a pipe with Ramda.js which accepts three arguments. The first function needs those three arguments, and it's result is used in the second function. However, the second function also needs one of the initial arguments. I cannot figure out the branching to build something like it. In pseudocode style, I need something like this: const composedFunction = R.pipe( firstFunction, secondFunction, ); const firstFunction = (reusedArgument, secondArgument, thirdArgument) => someAnswer;

问题 I'm building a pipe with Ramda.js which accepts three arguments. The first function needs those three arguments, and it's result is used in the second function. However, the second function also needs one of the initial arguments. I cannot figure out the branching to build something like it. In pseudocode style, I need something like this: const composedFunction = R.pipe( firstFunction, secondFunction, ); const firstFunction = (reusedArgument, secondArgument, thirdArgument) => someAnswer;

问题 I'm having trouble understanding the signature of Ramda docs. For example if you look at map you see this Functor f => (a → b) → f a → f b I don't see how this pattern fits the example: var double = x => x * 2; R.map(double, [1, 2, 3]); //=> [2, 4, 6] The functor in this example is [1,2,3] , so how does that get placed into the signature of f in Functor f => (a → b) → f a → f b ? Also, what do the → mean? 回答1: I'll give a brief answer here, but a more complete one is spread across two answers

问题 I'm having trouble understanding the signature of Ramda docs. For example if you look at map you see this Functor f => (a → b) → f a → f b I don't see how this pattern fits the example: var double = x => x * 2; R.map(double, [1, 2, 3]); //=> [2, 4, 6] The functor in this example is [1,2,3] , so how does that get placed into the signature of f in Functor f => (a → b) → f a → f b ? Also, what do the → mean? 回答1: I'll give a brief answer here, but a more complete one is spread across two answers

问题 I'm having trouble understanding the signature of Ramda docs. For example if you look at map you see this Functor f => (a → b) → f a → f b I don't see how this pattern fits the example: var double = x => x * 2; R.map(double, [1, 2, 3]); //=> [2, 4, 6] The functor in this example is [1,2,3] , so how does that get placed into the signature of f in Functor f => (a → b) → f a → f b ? Also, what do the → mean? 回答1: I'll give a brief answer here, but a more complete one is spread across two answers

问题 I'm learning javascript FP by reading DrBoolean's book. I searched around for functional programming library. I found Ramda and Folktale. Both claim to be functional programming library. But they are so different: Ramda seems to contain utility functions for dealing with list: map, reduce, filter and pure functions: curry, compose. It doesn't contain anything to deal with monad, functor. Folktale however doesn't contain any utility for list or functions. It seems to implement the some

问题 Looking at the source for Ramda.js, specifically at the "lift" function. lift liftN Here's the given example: var madd3 = R.lift(R.curry((a, b, c) => a + b + c)); madd3([1,2,3], [1,2,3], [1]); //=> [3, 4, 5, 4, 5, 6, 5, 6, 7] So the first number of the result is easy, a , b , and c , are all the first elements of each array. The second one isn't as easy for me to understand. Are the arguments the second value of each array (2, 2, undefined) or is it the second value of the first array and the