Modify the DewPoint and WindChill functions in weather.js to implement these more robust definitions. In particular, both functions should return NaN if called with invalid inputs, and the WindChill function should be updated to handle calm winds. Test your modified functions in your indexes.html page to verify that they behave as desired.

Question

What will be an ideal response?

Answer 1

```
function WindChill(temp, wind)
// Assumes: temp is a temperature in Fahrenheit,
// wind is wind speed in miles per hour
// Returns: the wind chill index (what the current conditions feel like)
{
if (temp >= 50) {
return NaN;
}
else if (wind <= 3) {
return temp;
}
else {
return 35.74 + 0.6123*temp + (0.4275*temp - 35.75)*Math.pow(wind, 0.16);
}
}

function DewPoint(temp, humidity)
// Assumes: temp is a temperature in Fahrenheit,
// humidity is the relative humidity (0-100%)
// Returns: the temperature at which water vapor condenses
{
if (humidity < 50) {
return NaN;
}
else {
return (temp - (100 - humidity)/2.778);
}
}
```