Metric Converter

        function solve(arr) {
            var number=Number(arr[0]);
            var input=arr[1];
            var output=arr[2];
            var meters=0;
            var result=0;

            switch(input){
                case "mm":
                {
                    meters=number/1000;
                    break;
                }
                case "cm":
                {
                    meters=number/100;
                    break;
                }
                case "mi":
                {
                    meters=number/0.000621371192;
                    break;
                }
                case "in":
                {
                    meters=number/39.3700787;
                    break;
                }
                case "km":
                {
                    meters=number*1000;
                    break;
                }
                case "ft":
                {
                    meters=number/3.2808399;
                    break;
                }
                case "yd":
                {
                    meters=number/1.0936133;
                    break;
                }
                case "m":
                {
                    meters=number;
                    break;
                }
            }

            switch(output) {
                case "mm":
                {
                    result=meters*1000;
                    console.log(result);
                    break;
                }
                case "cm":
                {
                    result=meters*100;
                    console.log(result);
                    break;
                }
                case "mi":
                {
                    result=meters*0.000621371192;
                    console.log(result);
                    break;
                }
                case "in":
                {
                    result=meters*39.3700787;
                    console.log(result);
                    break;
                }
                case "km":
                {
                    result=meters*0.001;
                    console.log(result);
                    break;
                }
                case "ft":
                {
                    result=meters*3.2808399;
                    console.log(result);
                    break;
                }
                case "yd":
                {
                    result=meters*1.0936133;
                    console.log(result);
                    break;
                }
                case "m":
                {
                    result=meters*1;
                    console.log(result);
                    break;
                }
            }

        } // end of solve