ramda.js

问题 I've got two lists: var listA = [ { Id: 2, Date: "2014-11-28", Amount: 30 }, { Id: 1, Date: "2014-11-27", Amount: 15 }, { Id: 1, Date: "2014-11-28", Amount: 20 }, ]; var listB = [ { Id: 1, Date: "2014-11-27", Amount: 15 }, { Id: 2, Date: "2014-11-26", Amount: 25 }, ]; I want to combine the data from both lists, grouping them by Id and using the highest date for each Id in the result, and summing the totals of the unique objects (ie. objects with the same Id and Date - there can only be one

问题 I have a method which requires multiple arguments, and I am trying to set up a ramda pipe to handle it. Here's an example: const R = require('ramda'); const input = [ { data: { number: 'v01', attached: [ 't01' ] } }, { data: { number: 'v02', attached: [ 't02' ] } }, { data: { number: 'v03', attached: [ 't03' ] } }, ] const method = R.curry((number, array) => { return R.pipe( R.pluck('data'), R.find(x => x.number === number), R.prop('attached'), R.head )(array) }) method('v02', input) Is there

问题 I have a need for a variadic version of R.either . After doing some searching around the web, I have not found a solution. R.anyPass would work but it returns a Boolean instead of the original value. Is there already a solution that I have overlooked? If not, what would be the most optimal way to write a variadic either utility function? An example: const test = variadicEither(R.multiply(0), R.add(-1), R.add(1), R.add(2)) test(1) // => 2 回答1: You could use a combination of reduce + reduced :

问题 I have a need for a variadic version of R.either . After doing some searching around the web, I have not found a solution. R.anyPass would work but it returns a Boolean instead of the original value. Is there already a solution that I have overlooked? If not, what would be the most optimal way to write a variadic either utility function? An example: const test = variadicEither(R.multiply(0), R.add(-1), R.add(1), R.add(2)) test(1) // => 2 回答1: You could use a combination of reduce + reduced :

问题 I have a need for a variadic version of R.either . After doing some searching around the web, I have not found a solution. R.anyPass would work but it returns a Boolean instead of the original value. Is there already a solution that I have overlooked? If not, what would be the most optimal way to write a variadic either utility function? An example: const test = variadicEither(R.multiply(0), R.add(-1), R.add(1), R.add(2)) test(1) // => 2 回答1: You could use a combination of reduce + reduced :

问题 I have a need for a variadic version of R.either . After doing some searching around the web, I have not found a solution. R.anyPass would work but it returns a Boolean instead of the original value. Is there already a solution that I have overlooked? If not, what would be the most optimal way to write a variadic either utility function? An example: const test = variadicEither(R.multiply(0), R.add(-1), R.add(1), R.add(2)) test(1) // => 2 回答1: You could use a combination of reduce + reduced :

问题 I'm wondering if there is a way by using a transducer for flattening a list and filter on unique values? By chaining, it is very easy: import {uniq, flattenDeep} from 'lodash';| const arr = [1, 2, [2, 3], [1, [4, 5]]]; uniq(flattendDeep(arr)); // -> [1, 2, 3, 4, 5] <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.10/lodash.core.min.js"></script> But here we loop twice over the list (+ n by depth layer). Not ideal. What I'm trying to achieve is to use a transducer for this

问题 I'm wondering if there is a way by using a transducer for flattening a list and filter on unique values? By chaining, it is very easy: import {uniq, flattenDeep} from 'lodash';| const arr = [1, 2, [2, 3], [1, [4, 5]]]; uniq(flattendDeep(arr)); // -> [1, 2, 3, 4, 5] <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.10/lodash.core.min.js"></script> But here we loop twice over the list (+ n by depth layer). Not ideal. What I'm trying to achieve is to use a transducer for this

问题 I'm wondering if there is a way by using a transducer for flattening a list and filter on unique values? By chaining, it is very easy: import {uniq, flattenDeep} from 'lodash';| const arr = [1, 2, [2, 3], [1, [4, 5]]]; uniq(flattendDeep(arr)); // -> [1, 2, 3, 4, 5] <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.10/lodash.core.min.js"></script> But here we loop twice over the list (+ n by depth layer). Not ideal. What I'm trying to achieve is to use a transducer for this

问题 I want to sort doubly linked list by next_id value. My DLL: const dll = [ {id: '22', prev_id: '41', next_id: '45'}, {id: '45', prev_id: '22', next_id: null}, {id: '41', prev_id: '14', next_id: '22'}, {id: '14', prev_id: null, next_id: '41'}, ] As a result: const dll_result = [ {id: '14', prev_id: null, next_id: '41'}, // next item - 41 {id: '41', prev_id: '14', next_id: '22'}, // next item - 22 {id: '22', prev_id: '41', next_id: '45'}, // next item - 45 {id: '45', prev_id: '22', next_id: null