Count all characters in string and output as string in ES6 Javascript

Question

Javascript implementation to print the characters and frequencies in the order of their occurrence. Please if anyone knows a better solution how to count characters in the string and output the result as a string as i dont like "converting an object to string" part.

See test cases below

function process (str) {
  
  //reject empty string
  if (!str) return "";
  
  //clean up
   str = str.replace(/[\s\W\d]/g, '').toLowerCase();
  
  //get result
  let result = str.split('').reduce((total, letter) => {
    total[letter] ? total[letter]++ : total[letter] = 1;
    return total;
  }, {});
  
   //convert to string
   let objToString = "";
   for (let key in result) {
     if (result.hasOwnProperty(key)) {
       objToString += `${key}${result[key]}`;
     }
   }
   return objToString;
}

//TEST
console.log('numbers', process('826'));
console.log('chars', process('**************'));
console.log('caps', process('ABC'));
console.log('spaces', process('AC  DC'));
console.log('mix', process('aaaa7682647828467823486^^&*^&*@^*@&*@^*@^*&^*&@^*&ssw1231323&*(&*(S&(*(*S(S&(23232132wwaaaabbbccccccccdddddd'));
console.log('mix', process('aabbbbccccdddddd'));

Layhout · Accepted Answer · 2022-07-27 04:43:29Z

1

hope this helped.

function process (str) {
    if (!str) return "";

    str = str.replace(/[\s\W\d]/g, '').toLowerCase();

    const result = [...new Set(str.split(""))].reduce((p, c) => {
        return p += c + (str.split(c).length - 1);
    }, "");

    return result;
}

answered Jul 27, 2022 at 4:43

Layhout

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Comments

zer00ne · Accepted Answer · 2022-07-27 05:18:50Z

Added a filter that can be modified via second parameter.

function chars(string, filter = 'all') {
  if (!string) return "";
  let rgx;
  switch (filter) {
    case 'a': // Alphabet
      rgx = /[A-Za-z]/;
      break;
    case 'd': // Digits
      rgx = /[\d]/;
      break;
    case 'u': // Uppercase
      rgx = /[A-Z]/;
      break;
    case 'l': // Lowercase
      rgx = /[a-z]/;
      break;
    case 's': // Whitespace
      rgx = /[\s]/;
      break;
    case 'x': // Other
      rgx = /[!`~@#$%&*\^\\\-\][_;:<>,.+=(){}|?/]/;
      break;
    case 'all': // All
      rgx = /[!`~@#$%&*\^\\\-\][_;:<>,.+=(){}|?/\s\dA-Za-z]/;
      break;
    default:
      break;
  }
  let result = string.split('').reduce((total, char) => {
    let letter = rgx.test(char) ? char : '';
    total[letter] ? total[letter]++ : total[letter] = 1;
    return total;
  }, {});
  // Filter all ''
  result = Object.fromEntries(Object.entries(result).filter(([k, v]) => k != ''));

  let objToString = "";
  for (let key in result) {
    if (result.hasOwnProperty(key)) {
      objToString += `${key}: ${result[key]}, `;
    }
  }
  return objToString.slice(0, -2);
}

//TEST
console.log('numbers', chars('826', 'd'));
console.log('chars', chars('**************', 'x'));
console.log('caps', chars('AaBCCCc', 'u'));
console.log('spaces', chars('AC  DC', 's'));
console.log('all', chars('aaaa7682647828467823486^^&*^&*@^*@&*@^*@^*&^*&@^*&ssw1231323&*(&*(S&(*(*S(S&(23232132wwaaaabbbccccccccdddddd'));
console.log('letters', chars('aaCCbbbBccccdddddd', 'a'));

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