Fibonacci Function Implementation in JavaScript

fibonacci.js

/**
* Fibonacci is a popular sequence known amongst both mathematicians and programmers.
* Fibonacci starts with 1,1 in the sequence and upon a specified iteration count
* will continue to add the last two numbers in the sequence.
*
* @author Mark Auger
* @social Follow me on GitHub at https://github.com/swimauger
* @license
* Copyright (c) 2021 Mark Auger
* 
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
* 
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
* 
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
* @param {number} i `i` is the number of iterations to make on fibonacci
* @param {number[]} sequence `sequence` is used to store the sequence on each iteration. DO NOT CHANGE.
* @return {number[]}
**/
function fibonacci(i, sequence = [ 1, 1 ]) {
  const x1 = sequence.pop(), x2 = sequence.pop();
  sequence.push(x2, x1, x1 + x2);
  
  if (i-- === 0) {
    return sequence;
  } else {
    return fibonacci(i, sequence);
  }
}