小程序页面js
let values = “jsonres[” + i + “].value”
that .setData({
[values]: value,
});

Page({
  /**
   * 页面的初始数据
   */
  data: {
    jsonres:[]
  },
  input_textarea: function (event) {
    let that  = this;
    var value=event.detail.value
    var index=event.target.dataset.index
    var json={
      value:value,
      index:index
    }
    var res=true
    var purchaselistTem = that.data.jsonres;
    that.data.jsonres.forEach((el, i) => {
      if(el.index==index){
        res=false
        let values = "jsonres[" + i + "].value"
        that .setData({
          [values]: value,
        });
      }
    });
    if(res){
      that .setData({
        jsonres: purchaselistTem.concat(json),
      });
    }
  }
})

页面textarea中bindinput事件 input_textarea

  <swiper class="productContentBox6" bindchange="fanye">
    <swiper-item style="width: 100%; display:inline-block;min-height:540rpx;">
      <view class="fuwuc2">
        <view>
          <text class="Keyword font-break">1、事故中，致害起因物是什么？</text>
          <view><textarea bindinput="input_textarea" data-idnex=0"  class="text1" placeholder="请输入内容"
              placeholder-style="color:#666;font-size:30rpx;" /></view>
            </view>
        </view>
      </swiper-item>
      <swiper-item style="width: 100%; display:inline-block;min-height:540rpx;">
      <view class="fuwuc2">
           <view>
              <text class="Keyword font-break">2、第二个测试问题？</text>
              <view><textarea bindinput="input_textarea" data-idnex="1"  class="text1" placeholder="请输入内容" placeholder-style="color:#666;font-size:30rpx;" /></view>
            </view>
          </view>
      </swiper-item>
    </swiper>