PieChart.js

import React, { Component } from "react";
import { Pie } from "react-chartjs-2";


export default class App extends Component {
    state = {
        dataPie: {
            datasets: [{
                label: 'Rating for intern',
                data: [50, 70, 20]
            }],
        },
        first: "",
        second: "",
    }
    handleSubmit = () => {        
        const { dataPie } = this.state;
        this.setState({
            dataPie: {
                ...dataPie,
                datasets: [{
                    ...dataPie.datasets,
                    data: [...dataPie.datasets[0].data,
                    this.state.first, this.state.second]
                }]
            }
        })
    }
    handleChange = (evt) => {
        let a = parseInt(evt.target.value)
        this.setState({
            [evt.target.name]: a,
        })
    }
    render() {


        const { data, dataPie } = this.state;
        console.log(dataPie);
        return (
            <React.Fragment>
                <input type="number"
                    value={this.setState.first}
                    name="first"
                    onChange={(evt) => this.handleChange(evt)} />
                <input type="number"
                    value={this.setState.second}
                    name="second"
                    onChange={(evt) => this.handleChange(evt)} />
                <button onClick={() => this.handleSubmit()}>Add Data</button>
                <h1>pie chart</h1>
                <Pie data={dataPie} />
            </React.Fragment>

        )
    }
}