Android Question parameters - Content-Type "json" to "x-www-form-urlencoded"

/* the following serialize and param methods are a version of zepto's
* https://github.com/madrobby/zepto/blob/601372ac4e3f98d502c707bf841589fbc48a3a7d/src/ajax.js#L344-L370
* modified to use _ (tested on lodash@4.6.1, should also work in underscore)
* to use with github's fetch:
     fetch(urrl, {
     method: 'post',
    headers: {
        'Accept': 'application/json',
        'Content-Type': 'application/x-www-form-urlencoded'
    }
    body: params({key1: "value1", key2: "value2"})
     })
*/
  
  function serialize(params, obj, traditional, scope){
    var type, array = _.isArray(obj), hash = _.isObject(obj)
    _.each(obj, function(value, key) {
      type = typeof value
      if (scope) key = traditional ? scope :
        scope + '[' + (hash || type == 'object' || type == 'array' ? key : '') + ']'
      // handle data in serializeArray() format
      if (!scope && array) params.add(value.name, value.value)
      // recurse into nested objects
      else if (type == "array" || (!traditional && type == "object"))
        serialize(params, value, traditional, key)
      else params.add(key, value)
    })
  }

  function param(obj, traditional){
    var params = []
    params.add = function(key, value) {
      if (_.isFunction(value)) value = value()
      if (value == null) value = ""
      this.push(encodeURIComponent(key) + '=' + encodeURIComponent(value))
    }
    serialize(params, obj, traditional)
    return params.join('&').replace(/%20/g, '+')
  }