How to assign value to a state variable inside fetchData?

Question

This is fetchData function used in my ReactJS class. It makes a call to API which returns an integer.

fetchData = () => {

    const url = "http://localhost:8000?"+
      'mytime='+this.state.mytime+
      '&mytype='+this.state.mytype;

    fetch(url, {
      method: "GET",
      dataType: "JSON",
      headers: {
        "Content-Type": "application/json; charset=utf-8",
      }
    })
    .then((resp) => {
      return resp.json()
    })
    .then((data) => {
      this.setState({
          chartData: [...this.state.chartData, {field1: this.state.field1, field2: data.field2}]
      })
    })
    .catch((error) => {
      console.log(error, "catch the hoop")
    })
};

I don't know how to assign this result ( data.field2 ) to this.state.field2 = data.field2 . How can I do it inside this code part:

.then((data) => {
      this.setState({
          chartData: [...this.state.chartData, {field1: this.state.field1, field2: data.field2}]
      })
    })

Answer 1

state = {
  chartData: ['A', 'B',
    {
      field1: 'C',
      field2: ''
    }
  ]
}

.then((data) => {
 const {chartData} = this.state;
 console.log(chartData[2].field2=data)
})

I try to set with this condition