to-be-or-not-to-be.js

/*

2704. To Be Or Not To Be

Given an array of functions [f1, f2, f3, ..., fn], return a new function fn that is the function composition of the array of functions.
The function composition of [f(x), g(x), h(x)] is fn(x) = f(g(h(x))).
The function composition of an empty list of functions is the identity function f(x) = x.
You may assume each function in the array accepts one integer as input and returns one integer as output.

Example 1:

Input: functions = [x => x + 1, x => x * x, x => 2 * x], x = 4
Output: 65
Explanation:
Evaluating from right to left ...
Starting with x = 4.
2 * (4) = 8
(8) * (8) = 64
(64) + 1 = 65

Constraints:

-1000 <= x <= 1000
0 <= functions.length <= 1000
all functions accept and return a single integer

*/

//solution

var expect = function(val) {
    return {
        toBe: (val2) => {
            if (val !== val2) throw new Error("Not Equal");
            else return true;
        },
        notToBe: (val2) => {
            if (val === val2) throw new Error("Equal");
            else return true;
        }
    }
};