AI solution for JavaScript Coding Question on BFE.dev
116. implement Object.is()

Sure, here's an implementation of Object.is():

function is(x, y) {
  if (x === y) {
    // Handle +0 == -0
    return x !== 0 || y !== 0 || 1 / x === 1 / y;
  } else {
    // Handle NaN == NaN
    return x !== x && y !== y;
  }
}

The function first checks if x and y are strictly equal (===) and returns true if so. However, it also checks for two special cases: if x and y are both 0, it returns false if one is positive and the other is negative. This correctly handles the fact that JavaScript distinguishes between positive and negative zero. If x and y are not strictly equal, the function returns true if both are NaN. This ensures that NaN is considered equal to itself, as required by the spec.