All Questions
97 questions
2
votes
2
answers
293
views
How to correctly identify pure functions in functional programming?
Is this function pure or impure?
function greet(name) {
return "Hi I'm " + name;
}
The property of pure function is that it has no side effects and always returns the same output for ...
2
votes
3
answers
215
views
How is injecting an impure function different from calling it?
I am reading a book where it says one way to handle impure functions is to inject them into the function instead of calling it like the example below.
normal function call:
const getRandomFileName = (...
- 475
1
vote
1
answer
391
views
How to Map an object's values regardless of its keys, and strongly type it (like Array<T>.map)
I'm in ES7/ES8, I want to know how to map an object's values, regardless of its keys (like Array.map).
I found this post here
But :
I am forced to map also the whole object, not the just value
I also ...
- 294
0
votes
1
answer
236
views
"Stringly typed" function vs. many redundant functions vs TypeScript's string enum
I have an object in the following structure:
const geo = {
europe: {
germany: ['berlin', 'hamburg', 'cologne'],
france: ['toulouse', 'paris', 'limoges'],
italy: ['rome', 'venice',...
- 4,241
0
votes
3
answers
113
views
Why type `Function` doesn't work when typing a higher-order function parameter that accepts a function?
I want to type a function that takes as inputs:
array
a function for filtering logic (predicate function)
In JavaScript, the following works as expected:
const myFilter = (func, arr) => arr....
- 4,241
1
vote
3
answers
78
views
Javascript - Loop two arrays inside another functional way
I have two arrays vehicles and routes, given below
const vehicles = [{ name: 'TukTuk', maxSpeed: 12 },
{ name: 'Bike', maxSpeed: 10 },
{ name: 'Car', maxSpeed: 20 }];
const routes = [{ name: '...
- 1,057
2
votes
4
answers
228
views
How to extract a function out of arr.map(elem => dict[elem])?
A function should do only one thing is considered a good practice when writing functions. However, I have a function that is already very minimal, but nevertheless I think it can be further extracted, ...
- 4,241
-1
votes
1
answer
79
views
How to change a function based on unknown number of arguments in javascript
Is there any way to add to or manipulate expressions in a returned function?
This is an example for a single argument:
function trackByProp(prop) {
return function (value) {
return value[prop];
...
- 156
0
votes
1
answer
321
views
Array Assignment in Functional Programming JS [closed]
When declaring a new local variable inside a function and assigning it to a global variable that is equal to an array, what is better?
Option 1: Using the Spread Operator:
let globalArray = [1, 2, 4];
...
- 57
0
votes
1
answer
974
views
Can a method be a pure function?
I'm learning functional programming. I have a very specific question.
Technically can a class method be considered a pure function?
Let's say we have an add method: add(a, b) { return a + b }. Is the ...
- 617
-1
votes
3
answers
279
views
Can we pass argument to function & access like a props in react
I have started learning to React/JavaScript recently, I found the way props are passed and accessed very interesting, I tried to make a similar JavaScript function in react which can simply take ...
- 1,657
6
votes
1
answer
965
views
Is this JavaScript function, taking a mutable reference argument, a pure function?
I have the same question as this one, but in the context of JavaScript.
From Wikipedia:
[a pure function's] return value is the same for the same arguments
It's further claimed there that a pure ...
- 39.7k
-1
votes
2
answers
123
views
List self nesting in Javascript
Question
I am trying to achieve a function that transforms a list into a second list with two sublist of itself. This function must do so by being called in a chain
i.e
[1,2,3] => [[1,2,3],[1,2,3]]...
- 390
4
votes
2
answers
1k
views
Recursive calls between two functions
I need to recursive check two objects and keys need to be sorted, so I created two functions.
buildObj - get all uniq keys from object, sort them and call buildObjKey on each key
buildObjKey - if one ...
- 536
0
votes
1
answer
58
views
What is the flow of execution with this compose function passed into Javascripts reduce?
I just want to know how reduce works in the case of code below(which was provided by a stackoverflow user in my previous question, i'm asking this question as his code snippet led to me having more ...
- 53