Recap: Typed Functions

Part of the Introduction To Luau section of Coddy's Lua journey. Lesson 29 of 73.

Challenge

Medium

Create a function type alias named NameFormatter for a function that takes two required strings and an optional string?, and returns a string.

Create a function named formatName of type NameFormatter (a local annotated with the alias). It receives firstName, lastName and an optional middleName:

When a middle name is provided, return "[firstName] [middleName] [lastName]"
Otherwise return "[firstName] [lastName]"

Read three input lines: the first name, the last name, and the middle name, which may be an empty line, meaning there is no middle name.

If the third line is empty (""), call formatName with only the two names; otherwise pass all three. Print the result.

Try it yourself

local firstName: string = io.read()
local lastName: string = io.read()
local middleName: string = io.read()

-- Write code here
-- type NameFormatter = (string, string, string?) -> string
-- local formatName: NameFormatter = ...
-- if middleName is "" call with two args, else with three