TypeScript 3.9+ update (May 12, 2020)
Now, TypeScript also supports named tuples. This greatly increases the understandability and maintainability of the code. Check the official TS playground.
So, now instead of unnamed:
const a: [number, string] = [ 1, "message" ];
We can add names:
const b: [id: number, message: string] = [ 1, "message" ];
Note: you need to add all names at once, you can not omit some names, e.g:
type tIncorrect = [id: number, string]; // INCORRECT, 2nd element has no name, compile-time error.
type tCorrect = [id: number, msg: string]; // CORRECT, all have a names.
Tip: if you are not sure in the count of the last elements, you can write it like this:
type t = [msg: string, ...indexes: number];// means first element is a message and there are unknown number of indexes.