Questions tagged [typescript]
Programming language created by Microsoft. Open source, and compiles to JavaScript.
128
questions
0
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1
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How could I apply the strategy pattern to a react component?
For the following component, how would I extract the unit logic to allow for composition? In my actual app I am trying to reduce the amount of logic encoded in the component and I have decided that ...
0
votes
1
answer
118
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How to Structure a Client Consuming an External API?
Context: I am building a site that is essentially just a UI for eBird's API.
My first question is about naming. Wikipedia defines a client as "a piece of computer hardware or software that ...
0
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2
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158
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Local development for TypeScript library organized as mono repo with Lerna
I currently am developing a TypeScript shared library. The library needs to be imported in sections to minimize the imported bundle size, so I broke it up into packages with a monorepo with Lerna. ...
- 51
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2
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219
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how to name functions that return booleans
I like the practice of naming boolean variables with a prefix like "is", "has", "should", or "can".
But what about the functions that produce those results?
...
- 137
-1
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1
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71
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Optimal OOP security for PubSub - Should mutual consent be required?
I am implementing the Publish-Subscribe pattern.
I have class Broker and interfaces IPublisher, ISubscriber.
interface IPublisher {
broker: Broker;
publish(channel: Channel, data: object): ...
- 145
1
vote
1
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71
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Querying objects in a list by class type vs string identifier - Best practices
I have a class Character who has a list of Spell objects that he can cast.
abstract class Spell {
name: string
manaCost: number
abstract cast() { ... }
}
class InvisibilitySpell extends ...
- 145
1
vote
0
answers
139
views
Should I extract my functions/types to new files in TypeScript?
Basically I have this class file which was getting quite large with functions and type definitions.
Is it best practice to keep all the code that works on the same aspect in the same file for "...
- 21
-1
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1
answer
228
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Right using monorepo for ts-node scripts
I have a repository with various tools/scripts written with ts-node and used in many projects.
Initially, it contained several automation/analytics scripts, one package.json file at the root, and one ...
- 99
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1
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84
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How to use Typescript to tag certain fields as Personally Identifiable Information, so they can be obfuscated in logging, etc
Using Typescript, if we imagine an entity like this:
interface Order {
id: string;
address: string;
}
Now I would like to design a system where we can process entities feeling confident that the ...
- 101
0
votes
1
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97
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design pattern advice on method of "injecting" html in React
Say I have a ReactNode post:
const Post = (props:{content:string}) => {
return(
<div>
{textProcessor(props.content)}
</div>
)
}
the role of textProcessor is to 1. to ...
- 151
1
vote
3
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344
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Best way to prevent people going overboard with Typescript?
I like typescript, and I want to add it to some projects in the company.
Thing is, it is rather powerful, probably too powerful for it's own good at times.
From experience, it doesn't take long until ...
user425023
1
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0
answers
28
views
Peer dependencies vs. (re-)exporting dependencies in abstract hierarchy (framework)
Say I have a module storage-abstract, which contains abstract logic (framework) for storing key/values. I also have some (arbitrarily many) implementations of this abstraction, each in a separate ...
- 129
1
vote
1
answer
107
views
What to use in B's configuration: A or A's configuration?
When I have a class A in a module amod as follows
// module amod
type AConfig = {
x: number;
// ...
};
class A {
constructor(public config: AConfig) {}
// ...
}
export {A, type AConfig}
...
- 129
0
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0
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56
views
How to efficiently retry/reprocess errors on a multi-actions service?
I have a service responsible for processing orders from an e-commerce, within this service, there are several actions that need to be performed, some in order and some not.
Example: Notify the user ...
- 383
0
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1
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162
views
Is it premature optimisation to test a condition to skip a small loop?
I have an array of entities which have an id property:
entities: {id: string|null}[] = [];
All items in the array are guaranteed to have id !== null and the array will not exceed 100 items.
Now I may ...
- 103
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0
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54
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Design a push events service at code level
In a large monorepo containing multiple micro-services, I need to build a service to push various events to several of them.
The event interface differs from service to service(one will have filed_5 ...
- 101
2
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3
answers
246
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Static types and dependencies in trunk-based development
There're certain things in code that can't be conditional. Two very common examples:
static types
dependencies.
You can't naturally enable/disable a feature that implies a new dependency or a new ...
- 139
1
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0
answers
45
views
Separating Typeorm Entities from Domain Entities [duplicate]
Is it a bad approach to add domain logic inside typeorm entities if following the domain model pattern to organize business logic.
import { Entity, PrimaryGeneratedColumn, Column } from "typeorm&...
- 67
1
vote
6
answers
1k
views
TDD: testing an abstract class. Test all concrete classes or create mock sub-class to test the behavior?
Well, I'm developing a personal project using TDD and Clean Architecture, and I chose to build an abstract class to gather all use-cases behavior in one single class. My question is: What you think ...
- 129
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1
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333
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What should I write before the tests in Clean Architecture with TDD?
Well, we all know the main concept of TDD: write a failing test, then implement the testing component to make your test pass.
I've been working on a personal project in Clean Architecture following ...
- 129
-3
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1
answer
783
views
Is it a bad practice to pass instance as function parameter? [closed]
So I am learning how to use the factory function in javascript/typescript. I created a to-do list project where I had to pass the instance as a parameter to the function. I wanted to ask is it a bad ...
0
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106
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Identify Domain Entities for a search tool interface - Clean Architecture
I am pretty new to Clean Architecture / Onion Achitecture, I actually not sure if the 2 terms are exchangeable.
So it pretty clear to me, considering is a few days I am reading and study about it.
It ...
0
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3
answers
242
views
Decoupling command and receiver in command pattern
I'm writing a simulation of a car that can receive commands and act on them and I'm trying to implement it using the command pattern.
class Car {
move() {
console.log('move');
}
}
interface ...
- 9
13
votes
6
answers
5k
views
Is it OK to have type aliases for primitive types in TypeScript?
In a project that my team is working on, we have type aliases for primitive types. The reason, I got from my team, for this is to have consistency across the codebase.
For example:
type FruitName = ...
- 241
0
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1
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179
views
Changing the generic type when chaining operations
I have a class where I want to chain certain operations. The class look something like this
class MyClass<T> {
create<X>(fn: (_: T) => X): MyClass<X> {
...
...
- 119
-1
votes
2
answers
183
views
What to do when forced to initialize functions in createContext
What do I do in this situation? Do I just initialize dummy functions in place of signup, login, and logout?
It seems so unnecessary since they are defined in AuthProvider.
type AuthContext = {
...
0
votes
1
answer
2k
views
Where should interfaces/model definitions live? -- Clean architecture
I'm working on a Node project (in typescript) that features a variation of clean architecture. I have a pretty clear understanding of the different layers of an application and how they depend on each ...
- 111
0
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1
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509
views
Removing successful cases from SQS batch. Is it wrong?
I have been working on a lambda that is triggered by a SQS with a batch (let's say of 5) and has automatic retry enabled.
The most common problem with this kind of setup that I have seen is that, if ...
- 119
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1
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69
views
Extending TypeScript while being futureproof [closed]
C#10 Has extended the property pattern ability, I think it began since #7
EG:
{ Car: { Interior: pattern } }
Meaning you can do some nice pattern matching even in if statements
if (car_var is ...
- 109
2
votes
1
answer
963
views
Is usage of "global" types in typescript considered bad practice?
I'm fairly new to strongly typed languages, coming from the "jungle" world of JS and PHP. In my current Typescript project(React-Typescript), i'm struggling with a very fundamental question: ...
- 125
2
votes
6
answers
598
views
Liskov Substitution Principle Inconsistency? How to figure out?
Liskov Substitution Principle states:
"if S is a subtype of T, then objects of type T may be replaced with objects of type S without altering any of the desirable properties of the program (...
- 137
1
vote
5
answers
1k
views
Clean architecture, Login UseCase with OAuth breaking Single responsability principle
I'm building a login system using OAuth to integrate with various social networks.
The flow is very simple, first, the user is redirected to their social network to grant permission to read the ...
- 383
1
vote
2
answers
234
views
Is it a good/bad practice to create overlapping types?
Here's a simple example: an API returns a list of possible options with the following structure:
{
"familystatus": [
{
"Id": 1,
"Name": "single&...
- 121
4
votes
3
answers
499
views
Steps to achieve the best code quality?
Currently I'm on a project where my objective is to obtain the best code quality.
We have unit, integration & e2e testing. The e2e tests are written by the Business team in cucumber and these ...
- 148
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votes
6
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455
views
Should a Car object be responsible for checking if it is able to run on certain Road objects?
I have 2 kinds of objects in my system, Car and Road.
A Car can be of various types and have properties like tire, tire size, engine, etc.
A Road can be of multiple types and have properties like ...
- 169
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1
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60
views
Pros and Cons of placing a method as static in the class or as private function outside of class when it doesn't utilize this?
I use TypeScript. When I write the below code ESlint throws this error: https://eslint.org/docs/rules/class-methods-use-this
export class {
constructor() {
const result = doCalculations()
......
- 109
0
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1
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93
views
How are discriminated unions (e.g. in TS) used in messaging schemes?
In the documentation about discriminated unions in typescript, here it says:
Discriminated unions are useful for more than just talking about
circles and squares. They’re good for representing any ...
- 127
2
votes
1
answer
318
views
When should a variable be declared / Value assigned?
So we have quiet a big TypeScript codebase at work, where each method resides in its own file. Now in a lot of those methods the variables are often declared all together at the top/beginnng of the ...
- 165
0
votes
2
answers
106
views
Language-independent explanation of "registration" by the IoC container
I've been reading quite a lot on the concept of Inversion of Control (IoC) and Dependency Injection (DI), and I've seen that DI often relies on an IoC container, which among other roles has to
...
- 61
5
votes
3
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495
views
Qualms over the 'flexibility' advantage of using dependency injection
I'm currently studying dependency injection and I'm having some issues with the so called 'flexibility' advantage of using dependency injection.
The flexibility advantage is mentioned in post ...
- 61
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1
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225
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Is a "wrong" to return anything else besides `this` in a constructor?
Is a "wrong" to return anything else besides this in a constructor?
Take this TypeScript Queue sample:
class Queue {
private buffer: string;
constructor(buffer: string = "&...
- 405
2
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2
answers
951
views
Domain driven design model version
sorry for the long question, but I love DDD but there is a problem I can't seem to resolve.
We have a problem when adding business rules to the aggregate root.
Our architecture is mostly like this ...
- 29
2
votes
0
answers
1k
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Setting width/height of unknown images for lazy loading
I have a site where users upload images & can all be viewed on a single page by other users. I want to lazy load images as the user scrolls instead of loading all initially. This is easy enough, ...
- 171
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1
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123
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Angular: send form or object?
My question is about clean code or best practice. I have a big formGroup and in my opinion its more difficult to map the form to an object than to send the form to the backend.
best regards
- 13
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0
answers
330
views
How do I architect reordering in database?
I'm building a todo list app and using react-beautiful-dnd on the frontend to allow users to reorder tasks. I'm trying to work out how to persist changes to the database when a user reorders items.
...
- 131
2
votes
2
answers
346
views
Should base class include unused properties of sub class?
I was looking at the angular documentation and noticed this code:
export class QuestionBase<T> {
value: T;
key: string;
label: string;
required: boolean;
order: number;
controlType: ...
- 177
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1
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128
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Use nullable or undefineable as object type?
This come with a debate with my colleague that I'm using nullable object type.
type Value = Node | null
const [v0, setV0] = React.useState<Value>(null)
const [v1, setV1] = React.useState&...
- 579
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109
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Preferred architecture for tree stuctured data (Angular/Typescript)
After reading some of "Clean Architecture" I got the idea that perhaps I should reconsider the way I have architected a chart of accounts/accounts object in an accounting program.
I have ...
- 103
28
votes
13
answers
9k
views
Ways to explain code when told it doesn't make sense
As a programmer I have found my code frequently elicits the reaction "I don't understand". Whenever I get this response I try my best to explain my code patiently, and not make anyone feel ...
- 500
4
votes
3
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2k
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Testing unexpected inputs for unit tests and loops?
I'm working on an enterprise that has some Angular/Typescript projects and to avoid repeating code (basically copying and pasting) between them, we decided to go for Monorepo and start write an util ...
- 151