React uncaught reference error: exports is not defined

Question

I am trying to add React to an existing Rails 5.1 application, but I'm getting this error: Uncaught ReferenceError: exports is not defined.

I'm using webpacker. This is the contents of my application.js file:

//= require react
//= require react_ujs
//= require components

In my components directory, I have the file register.jsx:

class Register extends React.Component {
    render(){
        return(
            <div>
                <h1>Register a Group</h1>
            </div>
        )
    }
}

export default Register

This file processes to this, as viewed in Chrome developer tools:

Object.defineProperty(exports, "__esModule", {
    value: true
});

var _createClass = (function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; })();

var _get = function get(_x, _x2, _x3) { var _again = true; _function: while (_again) { var object = _x, property = _x2, receiver = _x3; _again = false; if (object === null) object = Function.prototype; var desc = Object.getOwnPropertyDescriptor(object, property); if (desc === undefined) { var parent = Object.getPrototypeOf(object); if (parent === null) { return undefined; } else { _x = parent; _x2 = property; _x3 = receiver; _again = true; desc = parent = undefined; continue _function; } } else if ("value" in desc) { return desc.value; } else { var getter = desc.get; if (getter === undefined) { return undefined; } return getter.call(receiver); } } };

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

function _inherits(subClass, superClass) { if (typeof superClass !== "function" && superClass !== null) { throw new TypeError("Super expression must either be null or a function, not " + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) Object.setPrototypeOf ? Object.setPrototypeOf(subClass, superClass) : subClass.__proto__ = superClass; }

// import React from 'react';

var Register = (function (_React$Component) {
    _inherits(Register, _React$Component);

    function Register() {
        _classCallCheck(this, Register);

        _get(Object.getPrototypeOf(Register.prototype), "constructor", this).apply(this, arguments);
    }

    _createClass(Register, [{
        key: "render",
        value: function render() {
            return React.createElement(
                "div",
                null,
                React.createElement(
                    "h1",
                    null,
                    "Register a Group"
                )
            );
        }
    }]);

    return Register;
})(React.Component);

exports["default"] = Register;
module.exports = exports["default"];

The uncaught reference is being thrown at the very first line.

Any ideas are greatly appreciated!

do you `import React from 'react-dom` in your `register.jsx` ???? — a_m_dev, Aug 20 '18 at 06:07

score 0 · Answer 1 · answered Aug 21 '18 at 10:52

React should be loaded from your application pack in app/javascripts/packs/application.js, not from app/assets/javascripts/application.js, as the default JavaScript compressor that Sprockets uses doesn't support ES6.

Your React components should be referenced from app/javascripts/components as well.

Also make sure you're importing React correctly in your component files:

import React from 'react-dom'

export default class Register extends React.Component {
    render() {
        return (
            <div>
                <h1>Register a Group</h1>
            </div>
        )
    }
}

React uncaught reference error: exports is not defined

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