Category "types"

In typescript, why do the | and & operators flip their meaning when used on function types?

In this code, example1 and example2 are confusing me: type F1 = (a: string, b:string) => void; type F2 = (a: number, b:number) => void; // re: example

Typescript: how to inference class type that implements an interface

Giving an interface interface IAnInterface { } How to reference and point to a class type that implements that interface! Meaning! Giving a class: class AClas

JSDoc equivalent to Typescript's `as const`?

I'm in an old project that is too huge to easily convert to Typescript, so I've been using JSDoc instead. The Typescript feature that I can't figure out how to

How to create a UUID template literal type in Typescript?

Did anyone suceed in writing a type for UUID in Typescript using the new template literal types? e.g.: const id:UUID = "f172b0f1-ea0a-4116-a12c-fc339cb451b6" T

Enforcing units on numbers using Python type hints

Is there a way to use Python type hints as units? The type hint docs show some examples that suggest it might be possible using NewType, but also those examples

Check if string is in string literal type

We use static type checking extensively, but we also need some simple runtime type checking. I'd love to use our static types for that runtime type checking. I'

How to specify python type hints for complex package as opencv or tensorflow?

I am building a python library and I writing a function like this: def addimg(image) -> None: now I want to specify the type of image as an OpenCV image (e.

Correctly declare interface or type for functions params

How to correctly declare type for param cardsByStatus inside function addCardsToStatus? It works for cardsByStatus: any, but it doesn't make sense for me. Error

Define an empty object type in TypeScript

I'm looking for ways to define an empty object type that can't hold any values. type EmptyObject = {} const MyObject: EmptyObject = { thisShouldNotWork: {},

error TS2322: Type 'Event' is not assignable to type 'string'. [(ngModel)]="todoItem" (keyup) ="addTodo()"

I'm trying to bind my input to be able to display string. But I've this error: Error: list.component.html:3:15 - error TS2322: Type 'Event' is not assignable to

Defining new types in Haskell

I am pretty new to Haskell, and I was wondering if one can define new types that are defined by lists of other types. For example, I assume a string is defined

Append to existing tuple in c++

i am trying to make a thing to store types in list. The best thing is to use a tuple. then to get the type i use tuple_element_t. But the problem is when append

Python type hint for (any) class

I want to type hint the following function: def get_obj_class(self) -> CLASS_TYPE: return self.o.__class__ CLASS_TYPE should denote classes. self.o could

Typing variables in Common Lisp

I read that CL supports optional typing (as in the language has this feature) which I would assume allos for faster code in many cases, but I can't seem to find

Long return type hint and pep8

I have a function that raises an E501 line too long (86 > 79 characters) warning when running pycodestyle. def my_function(arg1: list = None) -> Tuple[pd.

make .d.ts for external library file available for project

I have a closed-source plain JS library that will be included via a <script> tag pointing to a CDN. I would like to author my own type definition file for

How to omit an union type depending on field value

I have this type (come from third party library): type StackActionType = { type: 'REPLACE'; payload: { name: string; key?: string | unde

How to include a global file type declaration in a TypeScript (Node.js) package

I'm working on a package that I am planning to publish publicly on npmjs. Let's call it the "text package". I would like that by default when installing that pa

Checking equality of interface{}

I am searching a []interface{} slice for a given interface{} value: var v interface{} for i := 0; i < len(A); i++ { if (A[i] == v) { fmt.Println("Gotc

Slick using mapped column type in update statement

I have a trouble in using slick MappedColumnType, the code snippet is as following: private trait UserTable { self: HasDatabaseConfigProvider[JdbcProfile] =&