1-printer-errors.js

// Exercise; https://www.codewars.com/kata/56541980fa08ab47a0000040/train/javascript

// In a factory a printer prints labels for boxes. For one kind of boxes the printer has to use colors which, for the sake of simplicity, are named with letters from a to m.

// The colors used by the printer are recorded in a control string. For example a "good" control string would be aaabbbbhaijjjm meaning that the printer used three times color a, four times color b, one time color h then one time color a...

// Sometimes there are problems: lack of colors, technical malfunction and a "bad" control string is produced e.g. aaaxbbbbyyhwawiwjjjwwm with letters not from a to m.

// You have to write a function printer_error which given a string will return the error rate of the printer as a string representing a rational whose numerator is the number of errors and the denominator the length of the control string. Don't reduce this fraction to a simpler expression.

// The string has a length greater or equal to one and contains only letters from ato z.

const printerError = (s) => {
    var totalCount = errorCount = 0;
    const errors = s.split('').filter((string) => {
        totalCount++;
        return (!string.match(/[a-m]/)) ? errorCount++ : '';
    });

    return errorCount + '/' + totalCount;
}


var s="aaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbmmmmmmmmmmmmmmmmmmmxyz"
console.log(printerError(s), "3/56")