BMI_calc.js

// Takes height in centimeters, converts it into meters and then squares the number.
const getHeight = function(height) {
  const cent = height / 100;
  const heightSquared = cent * cent;
  return heightSquared;
}
//Converts feet and inches into centimeters.
const feetAndInches = function(heightFt, heightIn) {
  const FtToInches = (heightFt * 12) + heightIn;
  return FtToInches/ 0.39370;
}

//Takes weight and divides it by height squared to get the BMI number.
const bmiCalc = function(weight, height) {
  const result = weight / getHeight(height);
  return result.toFixed(2);
}
//Divides weight into the BMI --- this will get multiplied in bmiResult to get ideal weight.
const idealWeight = (bmi, weight) => weight / bmi;

//Get input
const vitalStatistics = function(weightKg, heightCm, heightFt, heightIn) {
  if (heightCm) {
    const height = getHeight(heightCm);
    return bmiResult(weightKg, heightCm)
  } else if (!heightCm) {
    const height = feetAndInches(heightFt, heightIn);
    return bmiResult(weightKg, height);
  }
}

//Outputs the results and reccomended weights.
function bmiResult(weight, height) {
  const bmi = bmiCalc(weight, height);
  const bottomWeight = (idealWeight(bmi, weight) * 18.6)
  const topWeight = (idealWeight(bmi, weight) * 24.9)
  const message = `Your ideal weight is between ${Math.floor(bottomWeight)}kg and ${Math.floor(topWeight)}kg.`
  if (bmi < 18.5) {
    return `Your BMI is ${bmi} which means you are under weight. ${message}`
  } else if (bmi <= 24.9) {
    return `Your BMI is ${bmi} which means you are at a healthy weight. ${message}`
  } else if (bmi <= 29.9) {
    return `Your BMI is ${bmi} which means you are overweight. ${message}`
  } else if (bmi >= 30) {
    return `Your BMI is ${bmi} which means you are obese. ${message}`
  } else {
    return 'Please input a valid height and weight';
  }
}
//Values are - weight KG, height Cm, height ft, heiht inches.
console.log(vitalStatistics(65,false ,5 ,5));