ramda.js

问题 I want to convert a hexadecimal string like bada55 into a Uint8Array and back again. 回答1: Vanilla JS: const fromHexString = hexString => new Uint8Array(hexString.match(/.{1,2}/g).map(byte => parseInt(byte, 16))); const toHexString = bytes => bytes.reduce((str, byte) => str + byte.toString(16).padStart(2, '0'), ''); console.log(toHexString(new Uint8Array([0, 1, 2, 42, 100, 101, 102, 255]))) console.log(fromHexString('0001022a646566ff')) Note: this method always completes. If the length of the

问题 I have been trying to use group by at multiple levels so that the object is grouped by tag, folder and report keys. I was able to groupby at single level but could not proceed further. const data = [{ "_index": "search_index", "_type": "search_type", "_id": "Co5EFxnqeo9ruq", "_score": 1, "_source": { "admin_tags": [], "type": "human", "folder": "Feature Samples", "url_t": "url_tdata", "users": [ 128 ], "agent_id": 2, "url": "url_data", "favorited_by": [20], "idx": 121, "path": "Report Samples

问题 How can I pipe on multiple data arrays? Ultimately I want to achieve something like this: const data = [{id: 1, data:100}, {id: 2, data: 200}, {id: 3, data: 3000}, ... ] I tried this, but didn't work: pipe( map(assoc('data', __, {})), map(assoc('id', multiply(100, prop('data', __)))) )(range(1, 1000)) If the approach is to use two pipes, then there has to be some way to pipe over two different arrays simultaneously. How can this be implemented? 回答1: I suggest this: R.map(n => ({id: n, data:

问题 const censusMembers = Object.freeze([ { id: 1, name: 'Bob' }, { id: 2, name: 'Sue' }, { id: 3, name: 'Mary', household_id: 2 }, { id: 4, name: 'Elizabeth', household_id: 6 }, { id: 5, name: 'Tom' }, { id: 6, name: 'Jill' }, { id: 7, name: 'John', household_id: 6 } ]); In this array, A dependent can be determined by the presence of a household_id. The household_id is a reference to the ID of the employee that that member is a depended of (ex in the censusMembers list 'Mary' is a dependent of

问题 I am attempting to use the Google Places API in order to get the place name of a location I am in. The returned data structure has the following types: descriptor1: 'street number' | 'neighborhood' | 'postcode' | 'route' | 'locality' | 'postal_town' | 'administrative_area_level_2' | 'administrative_area_level_1' | 'country' places: [ { address_components: [{ long_name: 'string', short_name: 'string', types: { 0: descriptor1, 1?: descriptor2 } }], other_fields not relevant here } ] There is no

问题 I have the following state { "array": [ [ "Name", "Phone", "Email" ] ], "indexes": { "Name": 0, "Phone": 1, "Email": 2 }, "tempInput": ["test@test.com","test2@test.com"], "tempDestination": "Email" } Now I want to create a function taking the object and dynamically inserting the input values as new rows into the 2d array with at the designated destination, ultimately returning { "array": [ [ "Name", "Phone", "Email" ], [ "", "", "test@test.com" ], [ "", "", "test2@test.com" ] ], "indexes": {

问题 I have the following state { "array": [ [ "Name", "Phone", "Email" ] ], "indexes": { "Name": 0, "Phone": 1, "Email": 2 }, "tempInput": ["test@test.com","test2@test.com"], "tempDestination": "Email" } Now I want to create a function taking the object and dynamically inserting the input values as new rows into the 2d array with at the designated destination, ultimately returning { "array": [ [ "Name", "Phone", "Email" ], [ "", "", "test@test.com" ], [ "", "", "test2@test.com" ] ], "indexes": {

问题 Based on the help of @ScottSauyet I have been able to create a function resolving static and promise based callbacks for an initial data object. Now I want to be able to pipe this data object through a series of callbacks, but run into trouble once I add multiple promises into the mix. Current setup // Libaries const R = require('ramda'); const fetch = require('node-fetch'); const Promise = require('bluebird'); // Input const data = { array: [['#', 'FirstName', 'LastName'], ['1', 'tim', 'foo'

问题 Assuming the follow object how is it possible to use Ramda to perform a nested update in a criteria given an application, criteria ID and data? const application = { id: 'a1', features: [ { id: 'f1', criterias: [ { id: 'c1' } ] }, { id: 'f2', criterias: [ { id: 'c2' }, { id: 'c3' } ] } ] } The function would look something like this: const updateCriteria = (application, criteriaId, data) => // magic... updateCriteria(application, 'c2', { name: 'foo' }) // output: { // id: 'a1', // features: [

问题 What is the difference between chain() (from ramda package) and map() in Javascript? In both functions the programmer inputs an object and some lambda/function and gets a certain calculation of it. Thanks. 回答1: Abstract Types chain and map each operate on an abstract type. map operates on any Functor . This is any item with a map function that obeys certain laws. chain operates on a Chain element. Similarly, this is something with a lawful chain function, as well as having lawful apply and