Temperature Converter

on codepen at https://codepen.io/kschuljak/pen/rNYmEBO

• converts between Celsius, Fahrenheit, and Kelvin
• displays converted temperature rounded to two decimal places and with appropriate unit
• displays error when no number is entered to convert
• if both conversion options are the same (ex, Celsius to Celsius) the number entered is the number displayed

Examples

function roundTwoDecimals(x) {
  let rounded = Number((Math.abs(x) * 100).toPrecision(15));
  return Math.round(rounded) / 100 * Math.sign(x);
}

const convertTemp = (x, inputUnitSelected, outputUnitSelected) => {
   // ... (code omitted for example - error handling if x is NaN)
   // selects correct conversion based on entered values
   // assigns the correct unit to display on result
   if (inputUnitSelected == "Kelvin"  &&  outputUnitSelected == "Celsius") {
      convertedOutputTemp = (x - 273.15);
      unit = "°C";
   } else if (inputUnitSelected == "Kelvin" && outputUnitSelected == "Fahrenheit") {
      convertedOutputTemp = (1.8 * (x - 273) + 32);
      unit = "°F";
   // ... (etc - code omitted for example)
   // if input and output unit are the same, return entered value (rounded to two decimals) 
   // entered value displayed with appropriate unit
   } else if (inputUnitSelected == outputUnitSelected) {
      convertedOutputTemp = x;
      if (outputUnitSelected == "Fahrenheit") {
         unit = "°F";
      } // ... (etc - code omitted for example)
   } else {
      convertedOutputTemp = "please double check conversion options";
      return;
   }
   let answer = roundTwoDecimals(convertedOutputTemp);
   return answer + '  ' + unit;
}