union-types Questions
2
Solved
I'm new to TypeScript and am trying to work with expo-av for audio playback.
The following code gives me an error: TS2339: Property 'error' does not exist on type 'AVPlaybackStatus'.
const { sound,...
Laylalayman asked 18/2, 2021 at 17:34
7
Solved
For example, I have a type:
type abc = 'a' | 'b' | 'c';
How to make a tuple type that contains all elements of the union at compile time?
type t = ['a','b', 'c'];
Plerre asked 12/3, 2019 at 17:2
2
Solved
I have a list of interfaces that extends one basic interface.
I have also some functions that can accept any of these interfaces.
I would like to create a new interface that describe that kind of p...
Scrummage asked 10/2, 2017 at 9:52
1
Solved
I'm trying to model my data in Typescript in the following manner. Main focus is the type MessageHandler that maps the type in a message with a callback that accepts that message. I followed the ha...
Honey asked 6/5, 2023 at 10:12
4
I get the following errors:
type Union = { type: "1"; foo: string } | { type: "2"; bar: number };
function doSomething = (object: Union) => {
const { foo } = object
// ^ T...
Retrochoir asked 15/1, 2021 at 20:26
2
Solved
Union types, also known as sum types are a powerful language feature that I find myself using often in TypeScript
something along the lines of:
let a: string | number = “hello”
a = 3
How would I a...
Stokeontrent asked 25/6, 2022 at 17:12
4
I've the following struct:
type testCase struct {
input string
isValid bool
}
I want to use this struct in multiple tests and input could be either a string or an intetc.
I can convert the int i...
Macao asked 11/2, 2022 at 12:43
4
Solved
I know I can define string union types to restrict variables to one of the possible string values:
type MyType = 'first' | 'second'
let myVar:MyType = 'first'
I need to construct a type like tha...
Choler asked 22/5, 2019 at 18:50
1
Solved
I want to write a single function that can add certain fields to Firebase message structs. There are two different types of message, Message and MulticastMessage, which both contain Android and APN...
Histogenesis asked 17/6, 2022 at 20:50
2
Solved
If I want to have a type that can be multiple possible types, Unions seem to be how I represent that:
U = Union[int, str]
U can be an int or a str.
I noticed though that TypeVars allow for option...
Substratum asked 17/11, 2019 at 18:42
2
Solved
I have a string literal union type that looks like this:
type LowerCaseNames = 'youku-frame' | 'youku' | 'mini-program' | 'tiktok-frame';
This is only an example, since my union type is a list of ...
Trainband asked 4/3, 2022 at 14:17
2
Solved
def func(df_a: pd.DataFrame, df_b: pd.DataFrame) -> (pd.DataFrame, pd.DataFrame):
Pylance is advising to modify this line with two solution proposed. What would be the pros and cons of each one...
Arly asked 31/1, 2022 at 16:54
1
So from:
export interface Category{
val: string;
icon: string
}
const categoryArray: Category[] = [
{
val: 'business',
icon: 'store'
},
{
val: 'media',
icon: 'video'
},
{
val: 'people',...
Wes asked 13/1, 2022 at 13:56
2
Solved
If the members of a union type share a property, and the type of that property can be used to discriminate between those members, I should be able to narrow the type within an if clause using typeo...
Kickback asked 14/12, 2021 at 10:48
3
Solved
Whenever I have to work with objects that have a combined union type, typescript complains about the properties that I try to access and I don't get autocompletion either. For example this:
interfa...
Serration asked 15/7, 2020 at 8:8
2
Solved
I wonder whether it's possible to “split” union types into the specific subtypes in TypeScript. This is the code I tried to use, it should be obvious what I'm trying to achieve from the snippet:
ty...
Footnote asked 22/10, 2018 at 13:54
0
As far as I can gather, the following two types are equivalent in Python:
Optional[Union[A, B]]
Union[A, B, None]
Is there a defined convention for which one to choose, such as a clause in PE...
Roxannroxanna asked 15/9, 2021 at 0:43
3
Solved
I am writing a type declaration file for a library I do not control. One of the methods accepts an array of strings as a parameter, but these strings can only be very specific values. Currently I a...
Anneliese asked 27/5, 2019 at 15:43
1
Solved
Typed array like $arrIntOnly = [Int[]]@(1, 2, 3) is useful to ensure that all elements are valid type, but is it possible to define multiple types like $arrIntOrString = [[Int | String][]]@(1, &quo...
Vegetate asked 21/7, 2021 at 2:6
3
Solved
Imagine the following simplified setup:
import { Action, AnyAction } from 'redux'; // interface Action<Type> { type: Type } and type AnyAction = Action<any>
export type FilterActionBy...
Manama asked 27/10, 2019 at 22:57
4
Solved
mypy is really handy and catches a lot of bugs, but when I write "scientific" applications, I often end up doing:
def my_func(number: Union[float, int]):
# Do something
number is either a float...
Caddis asked 19/6, 2018 at 12:33
2
Solved
I'm using typescript on a project and in some parts of it I have to use union types. But I'm getting some weird error messages that I don't know how to deal with.
Consider the type below:
type body...
Nix asked 9/6, 2021 at 18:10
2
Solved
I've the following tagged union interface
interface Example {
a: TypeA;
b: TypeB;
}
as an output I would like to convert this tagged union into an union type such as:
type oneOf<T> = ...
...
Clypeus asked 26/6, 2020 at 8:49
1
Solved
An example:
type TA = {a:number,b:number}
type TB = {a:number,c:number,d:number}
const t1:Or<TA,TB> = {a:1,b:1} // want
const t2:Or<TA,TB> = {a:1,c:1,d:1} // want
const t3:Or<...
Corsair asked 26/2, 2021 at 9:11
2
Solved
Is it possible to allow an Array or an object that implements ArrayAccess?
For example:
class Config implements ArrayAccess {
...
}
class I_Use_A_Config
{
public function __construct(Array $te...
Nora asked 11/2, 2013 at 5:58
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