Update query params in URI

updateQuery.js

export default function updateQuery(params) {
  window.location.search = encodeURIParams(mergeObjects(decodeURIParams(), params), true);
};

function decodeURIParams(query) {
  if (query == null) {
    query = window.location.search;
  }
  
  if (query[0] == '?') {
    query = query.substring(1);
  }

  var params = query.split('&');
  var result = {};
  for (let i = 0; i < params.length; i++) {
    const param = params[i];
    const pos = param.indexOf('=');
    if (pos >= 0) {
      const key = decodeURIComponent(param.substring(0, pos));
      const val = decodeURIComponent(param.substring(pos + 1));
      result[key] = val;
    } else {
      const key = decodeURIComponent(param);
    }
  }
  
  return result;
}

function encodeURIParams(params, addQuestionMark) {
  const pairs = [];
  for (const key in params) if (params.hasOwnProperty(key)) {
    const value = params[key];
    if (value != null) /* matches null and undefined */ {
      pairs.push(encodeURIComponent(key) + '=' + encodeURIComponent(value))
    }
  }
  if (pairs.length == 0) {
    return '';
  }
  
  return (addQuestionMark ? '?' : '') + pairs.join('&');
}

function mergeObjects(destination, source) {
  for (var key in source) if (source.hasOwnProperty(key)) {
    destination[key] = source[key];
  }

  return destination;
}