小程序中字符串的JSON数据如何转换为Number类型

/** index.js*/var app = getApp()  Page({      data: {          /**            * 页面配置           */          winWidth: 0,          winHeight: 0,          // tab切换            currentTab: 0,                 option1:[          {value:"1",contant:"A:xxxx"},          {value:"2",contant:"B:xxxx"},          {value:"3",contant:"C:xxxx"},          {value:"4",contant:"D:xxxx"}        ],        option2: [          { value: "1", contant: "A:xxxx" },          { value: "2", contant: "B:xxxx" },          { value: "3", contant: "C:xxxx" },          { value: "4", contant: "D:xxxx" }        ],         option3: [          { value: "1", contant: "A:xxxx" },          { value: "2", contant: "B:xxxx" },          { value: "3", contant: "C:xxxx" },          { value: "4", contant: "D:xxxx" }        ],        option1Value:0,        option2Value:0,        option3Value:0,    },      onLoad: function() {   swiperChange: function(e){                var that = this;        if(that.data.currentTab==0){          that.setData({            option1Value : e.detail.value,            currentTab: 1           });        }else if(that.data.currentTab==1){          that.setData({            option2Value : e.detail.value,            currentTab: 2          });        }else if(that.data.currentTab==2){          that.setData({            option3Value : e.detail.value,            currentTab: 3          })        }          }   })  <!-- index.wxml -->                    <!-- 问题区域 --><view class="swiper-tab">        <view class="swiper-tab-list {{currentTab==0 ? 'on' : ''}}" data-current="0" bindtap="swichNav">第一题</view>        <view class="swiper-tab-list {{currentTab==1 ? 'on' : ''}}" data-current="1" bindtap="swichNav">第二题</view>        <view class="swiper-tab-list {{currentTab==2 ? 'on' : ''}}" data-current="2" bindtap="swichNav">第三题</view>      </view>                    <!-- 选项区域 --><swiper current="{{currentTab}}" class="swiper-box" duration="300" style="height:{{winHeight - 31}}px" bindchange="bindChange">                        <!-- 第一题选项 -->        <swiper-item>          <radio-group bindchange="swiperChange">        <label class="option" wx:for="{{option1}}">          <radio value="{{item.value}}" />{{item.contant}}        </label>      </radio-group>       </swiper-item>                        <!-- 第二题选项 -->        <swiper-item>          <radio-group bindchange="swiperChange">        <label class="option" wx:for="{{option2}}">          <radio value="{{item.value}}" />{{item.contant}}        </label>      </radio-group>       </swiper-item>                      <!-- 第三题选项 -->        <swiper-item>          <radio-group bindchange="swiperChange">        <label class="option" wx:for="{{option3}}">          <radio value="{{item.value}}" />{{item.contant}}        </label>      </radio-group>       </swiper-item>      <swiper-item>            <view>{{score}}</view>    </swiper-item>

以上是我的代码，想实现页面中有三个题目，分别有四个不同分值的选项，用户选择后直接弹出结果，但是储存用户选择的选项的JSON数据是字符串，请问如何转换为数字类型？