Optional Tuple Elements in TypeScript

Tuples can have optional elements, for which a value may not be specified. To indicate that an element is optional, a question mark is placed after the element type.

For example, in the tuple with the user, we will make one more optional element:

typescriptlet user: [string, number, boolean?];

Let's fill our tuple by specifying the third element:

typescriptuser = ['john', 31, true];

Now let's fill the tuple by omitting the third element:

typescriptuser = ['john', 31];

typescriptlet date: [number, number?, number?];