An intermediate transliteration function that handles substrings during substitution but not other edge cases

transliterate-sorted.js

// An intermediate transliteration function that handles substrings
// but does not handle other edge cases
const sortedTransliterate = (string = '', substitutions = {}) => {
  
  // save the string to a new variable for readability
  let str = string;
  
  // get the list of substitutions
  Object.entries(substitutions)
  
  // sort the substitutions by longest string (avoids the substring problem)
  .sort(([a], [b]) => b.length - a.length)
  
  // for each substitution...
  .forEach(([input, replacement]) => {
    
    // create a regular expression that searches globally for the string to replace
    const regexp = new RegExp(input, 'gu');
    
    // then replace all matched instances of the regular expression with the new string
    str = str.replace(regexp, replacement);
    
  });
  
  // return the string with the substitutions made
  return str;
  
};