JavaScript one-liner function: fibonacci (get single fibonacci number)

fibonacci.js

// =========================================================================
// https://en.wikipedia.org/wiki/Fibonacci_number#List_of_Fibonacci_numbers
// =========================================================================

// for ES2015
{
  const fibonacci = Object.assign(function f(n){return +n!==parseInt(n)||!isFinite(n)?NaN:Math.abs(n)>1476?Math.sign(n)*Infinity:(n>=0?1:~n%2?-1:1)*(f[Math.abs(n)]||(f[Math.abs(n)-1]=f(Math.abs(n)-1))+f[Math.abs(n)-2])},{"-2":-1,"-1":1,0:0,1:1});


  const positiveIntegers = [...[...Array(21).keys()], 100, 999, 1476, 1477, 1478, 1479];
  const negativeIntegers = positiveIntegers.map(c => -c);
  const notIntegers = [true, false, "", null, undefined, NaN, Infinity, -Infinity, 0.5, -0.5];

  for (p of [...positiveIntegers, ...negativeIntegers, ...notIntegers]) {
    const t = isFinite(p) ? JSON.stringify(p) : p;
    console.log(`${t} is ${fibonacci(p)}`);
  }
}

// for ES2015
{
  const fibonacciGenerator = function* (max=1476) {
    for (let [i, current, next] = [0, 0, 1]; i < max; i++) {
      yield current;
      [current, next] = [next, current + next];
    }
  };

  const fibonacciNumbers = [...fibonacciGenerator()];
  console.log(JSON.stringify(fibonacciNumbers));
  console.log(JSON.stringify("length: " + fibonacciNumbers.length));
}

https://stackoverflow.com/questions/426579/javascript-fibonacci-nth-term-optimization#answer-45793605