React Component to read its own source code, demo at: https://codesandbox.io/s/kmlmzlvn5v

ReactReader.js

import React, { Component } from "react";
import ReactDOM from "react-dom";

class App extends Component {
  constructor(props) {
    super(props);
    this.state = {
      result: ""
    };
  }

  componentDidMount() {
    const blob = new Blob([App]);
    const reader = new FileReader();
    reader.addEventListener("loadend", () =>
      this.setState(() => {
        const { result } = reader;
        return { result };
      })
    );
    reader.readAsText(blob);
  }

  render() {
    const { result } = this.state;
    return <div>{result}</div>;
  }
}

const rootElement = document.getElementById("root");
ReactDOM.render(<App />, rootElement);