COMPOSITION

The COMPOSITION Function

Function Group: Special

COMPOSITION takes a set of functions as its arguments and returns a function that is the result of the sequential application of those functions, evaluating the rightmost expression first and yielding the result to the next function (directly to the left of the function just executed).

Syntax

COMPOSITION(args...)

• args is a set of functions

Uses

Let's say we want to design a function that joins two strings and then capitalizes the result. Given the following data sample:

{
  "user_one": {
    "first_name": "Andrey",
    "last_name": "Rudenko"
  },
  "user_two": {
    "first_name": "Kirill",
    "last_name": "Chernyshov"
  }
}

We could write the function MAP(composition(UPPER, CONCATENATE), [[user_one.first_name, user_one,last_name], [user_two.first_name, user_two.last_name]]).

This would return: ["ANDREYRUDENKO","KIRILLCHERNYSHOV"].