Do loop with a switch case in javascript-CodePudding

//I need to add one to the total each time the error name is input. For example if I type "S" in the prompt, then it will add 1 to the total steering and if I type "W", it will add to wiper. The loop should run until i entered a null or zero value and calculate the total errors.

<html>
        <head><title>Charge Calculator</title></head>
        <body>
            <script type="text/javascript">
    
            
            //Declaring Variables
            var day;
            var data="";
            var steering = 0;
            var turbo =0;
            var wiper =0;
            day = prompt("Enter day: ","");
            var BR="<br/>";

            
    
            
            do
            {
            data = prompt("Enter Data: ","");
            data = input.nextLine();
            switch(data)
            {
            case 'S':
            steering  ;
            break;      
            case 'T':
            turbo  ;
            break;
            case 'W':
            wiper  ;
            break;      
            }
        
            }
            while(data == "")   
            document.write("day: "  day  BR); //Display destination name
            document.write("Steering issue: "  steering  BR);
            document.write("turbo Issue: "  turbo  BR);
            document.write("wiper Issue: "  wiper  BR);
            
            </script>
        </body>
    
    </html>

CodePudding user response：

There are many things to be improved in your code. Be aware that the write() expression will potentially destroy parts of your html-based page. Find out about DOM manipulation commands instead.

The following snippet demonstrates in a very short way how you could collect your inputs. I used your prompt() method simply to show that it can be done but I would always prefer a simple input field instead.

const counts={s:0,t:0,w:0};

while (  counts[prompt("Please enter the error type code (s,t or w):").toLowerCase()]) {}

console.log("steering: " counts.s 
      "\nturbo: " counts.t 
      "\nwipers: " counts.w);

Everything happens within the expression that calculates the result for the while condition: the input value is converted to lower case and then a property of the object counts will be incremented. This will only work (= return a "truthy" result) for already initialised properties like s, t or w. For all other cases an increment cannot be calculated, resulting in an "NaN" ("not a number") result. This will then end the while loop.

CodePudding user response：

Seems like recursion could be more appropriate solution here. Though @Cartsten's one looks absolutely ok also.

function count() {
  const counts = {
    s: 0,
    t: 0,
    w: 0
  };

  const checkCounts = () => {
    let input = prompt(
      'Please enter the error type code (s,t or w):'
    ).toLowerCase();

    if (counts[input] !== undefined) {
        counts[input];
      return checkCounts();
    }
  };

  checkCounts();

  console.log(
    `steering: ${counts.s} \n turbo: ${counts.t} \n wipers: ${counts.w}`
  );
}

count();