create-react-app Uncaught (in promise) SyntaxError: Unexpected token < in JSON at position 0

Question

Trying to read data from json dynamically using Highcharts in React. Throwing in the towel and appealing to SO for help.

Keep getting:

"Uncaught (in promise) SyntaxError: Unexpected token < in JSON at position 0"

no matter where I put the file. Ejecting from create-react-app and changing the Webpack config was no help.

Network tab shows a 200 response.

JSON is valid. Have tried to read json from both src and public folder. Have tried using fetch with headers and without. (Using with headers changes 200 to 404).

headers: {
  'Accept': 'application/json',
  'Content-Type': 'application/json'
  }
}

console.log(response.headers.get('Content-Type'))

returns text/html; charset=UTF-8 text/html; charset=UTF-8 .

Have tried the solutions here and here .

Here's the component:

Chart.js

import React, { Component } from 'react';
import HighchartsReact from 'highcharts-react-official';
import Highcharts from 'highcharts';

const endpoint = '../public/dummy.json'

export default class Chart extends Component {
  constructor(props) {
    super(props);

    this.state = {
      // To avoid unnecessary update keep all options in the state.
      chartOptions: {
        chart: {
          type: 'bar'
        },
        xAxis: {
          title: {
            text: 'X Axis'
          }
        },
        yAxis: {
          title: {
            text: 'Y Axis'
           },
          min: 0,
          max: 100
        },
        series: [
          { data: [6] }
        ],
        plotOptions: {
          series: {
            point: {
              events: {
                mouseOver: this.setHoverData.bind(this)
              }
            },
            name: 'Chart name'
          }
        }
      },
      hoverData: null
    };
  }

  setHoverData = (e) => {
    console.log(e)
    // The chart is not updated because `chartOptions` has not changed.
    this.setState({ hoverData: e.target.options.x })
  }

  updateSeries = () => {
    // The chart is updated only with new options.
    this.setState({
      chartOptions: {
        series: [
          { data: [Math.random() * 100]}
        ]
      }
    });
  }


    componentDidMount() {
      // fetch(endpoint, {
      //   headers: {
      //     'Accept': 'application/json',
      //     'Content-Type': 'application/json'
      //   }
      // })
      fetch(endpoint)         
      .then((response) => {
        response.json()
        console.log(response.headers.get('Content-Type'))
      })
      .then(data => {
        this.state.chartOptions.series[0].data = data;
        this.setState({ data: data });
      })
      // .catch(error => {
      //   console.log('Error! ', error)
      // })
    }


  render() {
    const { chartOptions, hoverData } = this.state;

    console.log('this.state: ', this.state)

    return (
      <div>
        <HighchartsReact
          highcharts={Highcharts}
          options={chartOptions}
        />
      <h3>Hovering over {hoverData}</h3>
      <button onClick={this.updateSeries.bind(this)}>Update Series</button>
      </div>
    )
  }
}

dummy.json

[
    {
        "first_name": "John",
        "amount": 10
    }, 
    {
        "fist_name": "Tim",
        "amount": 8 
    }
]

index.js

import ReactDOM from 'react-dom';
import Chart from './Chart'

ReactDOM.render(<Chart />, document.getElementById('root'));

Answer 1

Short Answer

Change ../public/dummy.json to just ./dummy.json since you are relative to the the root level of the public folder as opposed to being inside a sibling folder to public like the src/ folder.

Long Explanation

Make the path only ./dummy.json since only what is inside the public folder is getting served up. Your react components are bundled into the js files linked to the index.html in your public folder. Therefore, your fetch requests are bundles/"compiled" into JS files in your public folder. Because of this, your relative file paths should be made with the assumption that you are within the public folder.