convert a query string to a JSON object

queryStringToJSON.js

export const queryStringToJSON = (query) => {
  const setValue = (root, path, value) => {
    if (path.length > 1){
      const dir = path.shift();
      if (typeof root[dir] == 'undefined') {
        root[dir] = path[0] === '' ? [] : {};
      }
      arguments.callee(root[dir], path, value);
    } else {
      if (root instanceof Array) {
        root.push(value);
      } else {
        root[path] = value;
      }
    }
  };


  const nvp = query.split('&');
  const data = {};

  for (let i of nvp) {
    const pair = nvp[i].split('=');
    if (!Array.isArray(pair) || pair.length !== 2) {
      continue;
    }
    const name = decodeURIComponent(pair[0]);
    const value = decodeURIComponent(pair[1]);
    let path = name.match(/(^[^\[]+)(\[.*\]$)?/);
    if (!Array.isArray(path) || path.length < 2) {
      continue;
    }
    const first = path[1];
    if (path[2]) {
      //case of 'array[level1]' || 'array[level1][level2]'
      path = path[2].match(/(?=\[(.*)\]$)/)[1].split('][')
    } else {
      //case of 'name'
      path = [];
    }
    path.unshift(first);
    setValue(data, path, value);
  }



  return data;
};