Generating Tweets from Server

// Server
function getRandomString({length}) { 
  const characterChoices = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789 "; 
  const characters = [];
  while (characters.length < length) {
    const randomIndex = Math.floor(Math.random() * characterChoices.length);
    characters.push(characterChoices[randomIndex]);
  }
  return characters.join('');
}
function getRandomInteger({min, max}) {
  return Math.floor((Math.random() + min) * (max - min));
}
function generateSuggestion(prefix) {
  const RATIO_EXACT_MATCH = 0.3;
  const RATIO_AUTOCORRECT = 0.1;
  
  if (Math.random() < RATIO_AUTOCORRECT) {
    return getRandomString({ length: getRandomInteger({min: 1, max: prefix.length}) })
  }
  
  if (Math.random() < RATIO_EXACT_MATCH) {
    return prefix;
  }
  return prefix + getRandomString({ length: getRandomInteger({min: 1, max: 10}) })
}
function getAutocompleteHandler(data) {
  const MAX_CHARS = 10;
  const NUM_AUTOCOMPLETE_RESULTS = 10;
  const RATIO_AUXILLERY_DATA = 0.1;
  
  if (data.length > MAX_CHARS) {
    return [];
  }
  
  const results = [];
  while (results.length < NUM_AUTOCOMPLETE_RESULTS) {
    const suggestion = generateSuggestion(data)
    if (results.find(result => result.suggestion === suggestion)) {
      continue;
    }
    
    if (Math.random() < RATIO_AUXILLERY_DATA) {
      for (let i = 0; i < 2; i++) {
        results.push({
          suggestion, 
          auxillery: getRandomString({ length: getRandomInteger({min: 5, max: 10}) }) 
        });
      }
    } else {
      results.push({ suggestion, auxillery: "" });
    }
  }
  return results;
}
const endpoints = {
  "/": {
    "get": () => "hello world"
  },
  "/autocomplete": {
    "get": getAutocompleteHandler
  }
}
// API library
function getFunction(url, data, callback) {
  const domain = url.substring(0, url.indexOf("/"));
  const endpoint = url.substring(url.indexOf("/"), url.length);
  callback(endpoints[endpoint]["get"](data));
}
const api = {
  get: getFunction
};