Code Tidbits: #23 No Else Return (Medium Post)

23-improvement-with-guard-pattern.js

function calcPercentage(number) {
  
  // Guard #1: Stop execution if it's not a valie number
  if(typeof number !== 'number') { 
    return 'Please enter valid whole number';
  }
  
  // By this point, you know if will be a valid number
  // Guard #2: Stop execution if number is greater than 1
  if (number > 1) {
    return 'Number must be less than 1'; 
  }
  
  // Finally by this point, you know all the conditions have been met 
  //  Now, it's safe to perform your execution 🎉
  return `${number * 100}%`;
}