TypeScript’s quirks: How inconsistencies make the language more complex
1–10 of 216 posts
Re: TypeScript’s quirks: How inconsistencies make the language more complex
#2C#:
int x
Java: int x
Cpp: int x
C: int x
Some fucking retards at MS derp corp... TypeScrap:
x: int
Re: TypeScript’s quirks: How inconsistencies make the language more complex
#3The first example doesn't bother me and I think it's a weak argument. TypeScript allows literals[1] as types[0] so it is trying to use the object as a type.
The correct use of:
printDog({
breed: "Airedale",
age: 3
})
printDog({
breed: "Airedale",
age: 3
} as Dog)
[1] https://www.typescriptlang.org/docs/handbook/advanced-types....
Re: TypeScript’s quirks: How inconsistencies make the language more complex
#4The first example doesn't bother me and I think it's a weak argument. TypeScript allows literals[1] as types[0] so it is trying to use the object as a type. The correct use of: printDog({ breed: "Airedale", age: 3 }) is to explicitly cast it: printDog({ breed: "Airedale", age: 3 } as Dog) [0] https://www.typescriptlang.org/play/index.html?ssl=1&ssc=1&p... [1] https://www.typescriptlang.org/docs/handbook/advanced-type…
Casting can hide errors. It's better to assign it to a variable first that has a type declaration.
const dog: Dog = {
breed: "Airedale",
age: 3
}
printDog(dog)
printDog(((): Dog => ({
breed: "Airedale",
age: 3
})())Re: TypeScript’s quirks: How inconsistencies make the language more complex
#5I don’t agree with the article’s claim that discriminated unions are just a JS compat feature. Many APIs type JSON serialised entities using a string property and this feature makes it very easy to write interfaces and code to work with them.
Re: TypeScript’s quirks: How inconsistencies make the language more complex
#6The first example doesn't bother me and I think it's a weak argument. TypeScript allows literals[1] as types[0] so it is trying to use the object as a type. The correct use of: printDog({ breed: "Airedale", age: 3 }) is to explicitly cast it: printDog({ breed: "Airedale", age: 3 } as Dog) [0] https://www.typescriptlang.org/play/index.html?ssl=1&ssc=1&p... [1] https://www.typescriptlang.org/docs/handbook/advanced-type…
The article is just describing quirks, not arguing against them. Specifically for the first example they said "I think that the TypeScript stance here isn’t wrong".
Re: TypeScript’s quirks: How inconsistencies make the language more complex
#7How does TypeScript ensure encapsulation if it doesn't have nominal types?
Edit: The article says "magical hidden properties".
Re: TypeScript’s quirks: How inconsistencies make the language more complex
#8How does TypeScript ensure encapsulation if it doesn't have nominal types? Edit: The article says "magical hidden properties".
You can hide some of your structure using "private". There are also branded types: https://github.com/spion/branded-types
Re: TypeScript’s quirks: How inconsistencies make the language more complex
#9How does TypeScript ensure encapsulation if it doesn't have nominal types? Edit: The article says "magical hidden properties".
Programming TypeScript has a section on “Simulating Nominal Types” [1]. You define a type that’s impossible to create naturally, and provide a function that asserts something is of that type.
type CompanyID = string & {readonly brand: unique symbol}
type OrderID = string & {readonly brand: unique symbol}
type UserID = string & {readonly brand: unique symbol}
type ID = CompanyID | OrderID | UserID
function CompanyID(id: string) {
return id as CompanyID
}
...
[1] https://learning.oreilly.com/library/view/programming-typesc...
Re: TypeScript’s quirks: How inconsistencies make the language more complex
#10How does TypeScript ensure encapsulation if it doesn't have nominal types? Edit: The article says "magical hidden properties".
You can use private to do it OO/Java style, but you don't need typescript for that: ES6 modules let you encapsulate stuff just fine without any type features.