You have two options, both demonstrated by a contrived example where I fade out a unordered list using jQuery. There are pros and cons to both approaches, I highlight both, and then provide my choice.
Option 1: Include the third party library in your index.html file
index.html
<head>
...
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
...
</head>
App.jsx
import React, { Component } from "react";
class App extends Component {
componentDidMount() {
// ** following two lines of code do the same thing
// using the first version, however, could potentially cause errors
// see "Referencing unimported libraries when using create-react-app"
$(this.refs.list).fadeOut(); // version 1
window.$(this.refs.list).fadeOut(); // version 2
}
render() {
return (
<ul ref="list">
<li>Item 1</li>
<li>Item 2</li>
</ul>
);
}
}
ReactDOM.render(<App />, document.getElementById("root"));
Referencing unimported libraries when using create-react-app
** If you are using create-react-app to scaffold your project, using the first version of code will throw errors. This is because create-react-app's default syntax linter (eslint) will throw errors during project compilation if you try to reference non-imported code (i.e. you never import $ from "jquery" since we reference the library in index.html). So when we referencing jQuery's global $ reference (which is very normal when using jQuery in the browser), we violate the basic principles of building modular JavaScript applications on Node.js. In Node, modules are the way of life and in those modules, we can only reference objects that we explicitly import. Without that explicit mention we technically break convention, hence the complaint from the linter.
Now both you and I know that the $ reference will become available once the application actually runs in the browser. When componentDidMount() is invoked, view has already mounted to the DOM and your third party library (in our example jQuery) is available to reference. Unfortunately the linter will block your react app from rendering because it thinks you are trying to reference undefined variables. Furthermore, the linter is platform agnostic and has no knowledge that your app is running in the browser (since JavaScript is no longer a browser-only language). This may be annoying but the linter is just doing its job, and, to some degree, it's absolutely right.
To avoid this error there are a few options:
- Have eslint (the provided linter) ignore the lines where you make
reference the third party libraries using
// eslint-disable-next-line (not preferred)
, or
- Make use of
window (preferred), or
- Turn off the linter (not preferred), or
- Don't use create-react-app (your preference, not recommend for beginners or even experts for that matter).
The first option can easily become a hassle if you make a lot of calls to the third party library. If you read up on componentDidMount, you know that at this point of invocation, you now have access to the window variable. You can access your library through window if the library attaches itself to the DOM's global window object. In our example, jQuery does just that and we can access jQuery's functionality via window.$
Option 2: Install the library using npm install <package-name> -S and import the library into relevant project files.
Terminal
npm i jquery -S
App.jsx
import React, { Component } from "react";
import $ from "jquery";
class App extends Component {
componentDidMount() {
$(this.refs.list).fadeOut();
}
render() {
return (
<ul ref="list">
<li>Item 1</li>
<li>Item 2</li>
</ul>
);
}
}
ReactDOM.render(<App />, document.getElementById("root"));
What is the right approach?
There are pros and cons of each approach: with first one you have the possibility of using a library that is hosted on a CDN and bank on the network effects and don't need to import third party code into your codebase. With the latter, you can make your code more readable and avoid the linter from blowing up.
For cons, the first approach may require you to add window to your third party library calls if you're using a linter (and you probably should); in the latter's case, sometimes third party libraries don't have their project code available to install through npm and you must download them manually and manually add them to your project source folder. In that case, using the first approach might make sense so that you don't have to manually import new versions of the library when they're released.
If at the end of all of this, you have failing code:
- Ensure you installed the correct package,
- Ensure you have included it directly in your index file or
imported it into your project and files where you are making library
specific calls.
If you know of other ways of accomplishing third party library integrations into react or find an error in this post, please feel free to edit this answer or add another answer.
The examples in this answer assume the execution environment is a browser, hence the use of window. If you are building a shell script or using react-native, it would be global, etc.
