custom function that behaves as ===

strictEquals.js

function strictEqual(a, b) {
  if ((Object.is(a, 0) && Object.is(b, -0)) || (Object.is(a, -0) && Object.is(b, 0))) {
    return true
  }

  if (Object.is(a, NaN) && Object.is(b, NaN)) {
    return false
  }

  return Object.is(a, b)
}

console.log(strictEqual(10, 10) === true)
console.log(strictEqual(undefined, undefined) === true)
console.log(strictEqual(null, null) === true)
console.log(strictEqual('10', '10') === true)
console.log(strictEqual({}, {}) === false)
console.log(
  strictEqual(
    function () {},
    function () {},
  ) === false,
)
console.log(strictEqual(Symbol(), Symbol()) === false)
console.log(strictEqual(1n, 1n) === true)
console.log(strictEqual(NaN, NaN) === false)
console.log(strictEqual(-0, 0) === true)