So basically, I was looking around discordjs's typings folder and found this:
export interface ClientEvents {
...
messageCreate: [message: Message] <- what?
messageDelete: [message: Message | PartialMessage]
}
What exactly are they trying to do here? I've heard of index signatures, like in this example here:
interface Foo {
[bar: string]: any
}
But I've never seen any syntax that resembles this in both TS and JS.
Credits to jonrsharpe's comment under the question. The syntax mentioned was a variation of a tuple in TypeScript 4.0 which includes labels:
Regular tuple:
// has no indication of parameter names
type Range = [number, number]
Labelled tuple:
type Range = [start: number, end: number]
// spreading this labelled tuple in a function's parameters...
function getRange(...range: Range)
// ... results in the following at compile time:
function getRange(start: number, end: number)
Very cool!