folktale | standard library for functional programming | Functional Programming library
kandi X-RAY | folktale Summary
kandi X-RAY | folktale Summary
[Dependencies status] ![Licence] Folktale is a standard library for functional programming in JavaScript.
Support
Quality
Security
License
Reuse
Top functions reviewed by kandi - BETA
Currently covering the most popular Java, JavaScript and Python libraries. See a Sample of folktale
folktale Key Features
folktale Examples and Code Snippets
Lines of Code : 40
License : No License
Copyconst config = require('config')
// config.get will throw if key doesn't exist
const getSecretKeyUnsafe = config => config.get('keys.gateway.secretKey')
// return an Object
const getSecretKeySafe = config => {
try {
const value = import eitherMiddleware from 'redux-either';
import { Either } from 'ramda-fantasy';
const store = createStore(
reducer,
initialState,
applyMiddleware(
eitherMiddleware(
Either, // the Either instance
Either.either // function t Community Discussions
Trending Discussions on folktale
QUESTION
I understand that monads typically don't want to unwrap the underlying value because it may or may not exist. In my use case I would like to use functional programming techniques, using ramda for a functional library and Crocks for an algebraic data structure library to write code in a not fully functional codebase. I'm typically going to be using Either, IO, and Maybe monads to write my code, but then extract the final result out of the resultant monad so I can return the value to a function that is not made to accept monads yet.
Folktale has something called getOrElse which will return a value or an undefined/error string. This is super useful and allows me to write functionally in an environment that does not expect to handle monads. Does Crocks have something similar or is there another way to unwrap an Either, IO, or Maybe?
Folktale example that I'd like to replicate in Crocks:
...ANSWER
Answered 2020-Oct-07 at 23:02Check out the example here, https://crocks.dev/docs/crocks/Result.html#either or https://crocks.dev/docs/crocks/Maybe.html#either I think it's the closest to what you're trying to do.
What you're essentially touching on is folding out the value. In this scenario you need to ensure that you can take a Maybe a and pass in two functions that are () -> b and a -> b where b is the return value of your function that does not want to return a Monad
QUESTION
I have 3 buttons that should change the behavior of the videos on the page depending on the chosen dropdowns. But the user chooses a choice from the dropdown, the videos don't cooperate.
This is the front end. When I choose something on for example language, the videos should change, but it doesn't.
The page ends up on http://localhost:8000/?language=EN&level=LEV&category=CAT then the page breaks
I tried adding a reverse_url on the views but it still didn't fix the error.
...ANSWER
Answered 2019-Sep-24 at 19:06In case you're not choosing any filter then the value of CATEGORY and LEVEL should be empty but there are 2 values CAT and LEV. That's why when you filter your video, there is no data returned.
Try to make your selects value as empty when you're not select it, by change your form like so:
QUESTION
I want to know how I can connect 2 models to create a dropdown which is dependent on each other.
As of writing, these are my models for the videos:
...ANSWER
Answered 2019-Sep-23 at 08:22You can handle that by using Django Form, which you can render in the template, keep filter value to send to the view. Like so:
forms.py
QUESTION
I've been trying to figure out how to implement dropdown buttons in Django but has not figured out what works.
What I created is:
...ANSWER
Answered 2019-Aug-27 at 06:15You can use Django Form in this case to create dropdowns on client side. You can use a form to hold the filter data and then when you create a form, you can add categories, languages, levels from your user profile into the form and put it into view context. Like so:
Filter form:
QUESTION
I have react 16.3.2, and today i attempted to upgrade it through yarn upgrade react@latest it has upgraded the yarn.lock's react@^16.8.2 but when I console.log out the react version it still outputs 16.3.2 Did I miss something?
Here's my package.json
ANSWER
Answered 2019-Feb-14 at 22:18yarn upgrade does not update package.json, only the lock file. Actually, none of the yarn upgrade flags do. There's a long discussion about this in here
You can do the following:
- Reinstall React with
yarn add react@latest - Install a npm package to check updates, for example, npm-check-updates. Run it to update
package.jsonand then tryyarn install. - Or you can install that specific React version
yarn upgrade react@16.8.2.
This is the intended behaviour, even though it is very confusing in the docs.
QUESTION
I want to use Node to fire up two child processes in a particular order at a particular time, console logging their stdout as they stream, occasionally switching between the two.
ANSWER
Answered 2018-Aug-23 at 23:33You're removing listeners from the proc instead of from stdout. The doubles are appearing because you're attaching a second copy of your listener to the 'data' events on the proc.stdout.
Adding .stdout in rmAllListeners fixes it for me:
QUESTION
I am reading every inch of the docs and trying to learn about Folktale as much as I can.
Recently, I decide to try Future.
Now while I understand the difference between Task and Promise and between Task and Future ( support for cancellation ) it is not clear to me the difference between Future and Promise.
Why would I ever want to use a Future instead of a Promise ? What benefits would I have?
Well, you can say: "This way you actually have a monad, instead of a sorry excuse for a monad".
And that is a fine argument on it's own but... having in mind I always need to convert from Promise to something else ( to future ) and that the Future's API is pretty much the same, it is not clear to me, as someone new, why I should care about Future at all.
Lets assume I have this function, where request is a function that makes a request and returns some results.
extractRequestInfo is a function that extracts data from the response object.
If something fails, I catch the error and return an object with all the data, the badId and the error.
ANSWER
Answered 2018-Jul-20 at 07:06Quoting the response from the creator Quil:
Future solves the same problem Promise does, so there isn't much of a conceptual difference between the two. The difference is more in how they solve the problem.
Promises can either settle successfully or fail. In any transformation you apply to a promise's value, errors thrown synchronously will be implicitly caught and reject the promise as well. This is interesting in async/await because you can handle these errors (synchronous and asynchronous) in a similar way--you don't need to lift every synchronous operation into a promise, because the runtime will do that for you.
The downside of this is that it's very easy to catch errors that you didn't intend to, and have your system run in an inconsistent state. I don't think you can do much with static analysis here either.
Futures don't have that problem because nothing is lifted into a future implicitly. If you want synchronous operations to use the Future pipeline for handling errors, you have to put them there explicitly. This gives you more control over error handling, and uncaught errors will still crash the process as expected (avoiding having your program run into inconsistent memory states for cases you didn't predict), but it takes more effort to write programs this way.
Other than that, if you consider Tasks, Futures model the eventual value of a Task with a success case, a failure case, and a cancellation case. Promises only have a success case and a failure case, so cancellation is modelled as a special failure value. This changes the idioms for handling cancellations a bit. It's possible for code using promises to handle failures without being aware of this special cancellation value, which may be a problem since this value may easily be lost during these transformations.
In codebases that mix promises and tasks, these problems are more complicated because the implicit-lifting of errors that promises do is not very compatible with the explicit-lifiting of errors that tasks/futures expect (this can lead to problems like this one: #163). Finding these bugs becomes a lot harder than if you had only promises or only tasks/futures. Not sure what's the best way to handle these cases yet.
For the original discussion:
QUESTION
In data.task package, I could resolve or reject a api call as following:
ANSWER
Answered 2018-May-31 at 23:22Ok this is really silly! For some reason I could not find this solution right away on the doc.That's why I imported the rejected from task...
Basically resolver function coming from task has not only resolve, but also reject, which should have been obvious, but it was not on the doc.
So here is working code:
QUESTION
I've been using Folktale's Validation on a new project and I've found it really useful, but I have hit a wall with the need for sequential validations. I have a config object and I need to perform the following validations:
- is is an Object?
- are the object's keys valid (do they appear on a whitelist)?
- are the values of the keys valid?
Each validation depends on the previous validation - if the item isn't an object, validating its keys is pointless (and will error), if the object has no keys, validating their values are pointless. Effectively I want to short-circuit validation if the validation fails.
My initial thought was to use Result instead of Validatio, but mixing the two types feels confusing, and I already havevalidateIsObject` defined and used elsewhere.
My current (working but ugly) solution is here:
...ANSWER
Answered 2018-Jan-10 at 16:51You can write a helper that applies validation rules until a Failure is returned. A quick example:
QUESTION
A task has a few steps, if each step's input is only from direct last step, it is easy. However, more often, some steps are depend on not only the direct last step.
I can work out via several ways, but all end up with ugly nested code, I hope anyone could help me to find better ways.
I created the following signIn-like example to demonstrate, the process has 3 steps as below:
- get database connection (() -> Task Connection)
- find account (Connection -> Task Account)
- create token (Connection -> accountId -> Task Token)
#step3 depends not only on step#2 but also step#1.
The below are the jest unit tests by using folktale2
...ANSWER
Answered 2017-Sep-06 at 23:18Your example could be written as follows:
Community Discussions, Code Snippets contain sources that include Stack Exchange Network
Vulnerabilities
No vulnerabilities reported
Install folktale
Support
Reuse Trending Solutions
Find, review, and download reusable Libraries, Code Snippets, Cloud APIs from over 650 million Knowledge Items
Find more librariesStay Updated
Subscribe to our newsletter for trending solutions and developer bootcamps
Share this Page
