I've been going through the typescript documentation for quite some time and I can't seem to find any examples regarding the below example for a type alias. I'm trying to understand what the purpose of the empty array is after the closing object brace.
Thanks!
type PostsProps = {
posts: {
tags?: {
name: string
slug: string
}[] // what is the purpose of this empty array
}[] // what is the purpose of this empty array
}
You can use an empty array to define an array type.
The empty array in the example code above basically defines the type of posts as an array of object(s) with a property of tags nested as another array of object(s) where there's name and slug properties which are both strings.
A simpler example, I could define a type for an array of strings like this
let color: string[];
color = ['red', 'green', 'more colors']; // This is ok
color = ['red', 'green', 5]; // This would flag
[] is special shorthand syntax for the Array type. So for example, string[] and Array<string> are equivalent.
A common code style is to use the short version for simple array types like number[], string[] or any[] while using Array for more complex types like Array<Record<string, string>>. However, as far as I know, TypeScript always displays the short syntax (in this case Record<string, string>[]) when you hover over the type.
