strictEquals.js

// Like a === b
function strictEquals(a, b) {
  if (Object.is(a, b)) {
    // We know a and b are equal so we check only a
    if (Object.is(a, NaN)) {
      // Special case #1.
      return false;
    } else {
      return true;
    }
  } else {
    if (
      (Object.is(a, 0) && Object.is(b, -0)) ||
      (Object.is(a, -0) && Object.is(b, 0))
    ) {
      // Special case #2.
      return true;
    } else {
      return false;
    }
  }
}