AingCreations Encoding. I miss AingCreations :'(

aingcreations-encoding.md

Encode/decode strings the AingCreations way. That is to map characters in a string to their respective indices and reconstructing the original string from that mapping

/**
 * @param {string} str - The string to encode.
 * @returns {object} - The object mapping each character to an array of its indices
 */
var encode = function(str) {
  var mapping = {};

  for (var i = 0; i < str.length; i++) {
    var char = str[i];

    if (!mapping[char]) {
      mapping[char] = [];
    }

    mapping[char].push(i);
  }

  return mapping;
};

/**
 * @param {object} mapping - The mapping of string characters
 * @returns {string} - The decoded string
 */
var decode = function(mapping) {
  var result = [];

  for (var char in mapping) {
    for (var i in mapping[char]) {
      var idx = mapping[char][i];
      result[idx] = char;
    }
  }

  return result.join("");
};

Example

var encoded = encode('aing'); 
console.log(JSON.stringify(encoded));
/** encoded: {"a":[0],"i":[1],"n":[2],"g":[3]} */

var decoded = decode(encoded);
console.log(decoded);