[javascript] Adding script tag to React/JSX

I have a relatively straightforward issue of trying to add inline scripting to a React component. What I have so far:

'use strict';

import '../../styles/pages/people.scss';

import React, { Component } from 'react';
import DocumentTitle from 'react-document-title';

import { prefix } from '../../core/util';

export default class extends Component {
    render() {
        return (
            <DocumentTitle title="People">
                <article className={[prefix('people'), prefix('people', 'index')].join(' ')}>
                    <h1 className="tk-brandon-grotesque">People</h1>
                    
                    <script src="https://use.typekit.net/foobar.js"></script>
                    <script dangerouslySetInnerHTML={{__html: 'try{Typekit.load({ async: true });}catch(e){}'}}></script>
                </article>
            </DocumentTitle>
        );
    }
};

I have also tried:

<script src="https://use.typekit.net/foobar.js"></script>
<script>try{Typekit.load({ async: true });}catch(e){}</script>

Neither approach seems to execute the desired script. I'm guessing it's a simple thing I'm missing. Can anybody help out?

PS: Ignore the foobar, I have a real id actually in use that I didn't feel like sharing.

This question is related to javascript reactjs ecmascript-6

The answer is


componentDidMount() {
  const head = document.querySelector("head");
  const script = document.createElement("script");
  script.setAttribute(
    "src",
    "https://assets.calendly.com/assets/external/widget.js"
  );
  head.appendChild(script);
}

A bit late to the party but I decided to create my own one after looking at @Alex Macmillan answers and that was by passing two extra parameters; the position in which to place the scripts such as or and setting up the async to true/false, here it is:

import { useEffect } from 'react';

const useScript = (url, position, async) => {
  useEffect(() => {
    const placement = document.querySelector(position);
    const script = document.createElement('script');

    script.src = url;
    script.async = typeof async === 'undefined' ? true : async;

    placement.appendChild(script);

    return () => {
      placement.removeChild(script);
    };
  }, [url]);
};

export default useScript;

The way to call it is exactly the same as shown in the accepted answer of this post but with two extra(again) parameters:

// First string is your URL
// Second string can be head or body
// Third parameter is true or false.
useScript("string", "string", bool);

To add script tag or code in head tag <head>, use react-helmet package. it is light and have good documentation.

To add Js code in script tag inside body,

    function htmlDecode(html) {
      return html.replace(/&([a-z]+);/ig, (match, entity) => {
        const entities = { amp: '&', apos: '\'', gt: '>', lt: '<', nbsp: '\xa0', quot: '"' };
        entity = entity.toLowerCase();
        if (entities.hasOwnProperty(entity)) {
          return entities[entity];
        }
        return match;
      });
    }
  render() {
    const scriptCode = `<script type="text/javascript">
          {(function() {
          window.hello={
            FIRST_NAME: 'firstName',
            LAST_NAME: 'lastName',
          };
          })()}
          </script>`
    return(
      <div dangerouslySetInnerHTML={{ __html: this.htmlDecode(scriptCode) }} />;
    );
  }

this code can be tested by console.log(windows.hello)


You can use npm postscribe to load script in react component

postscribe('#mydiv', '<script src="https://use.typekit.net/foobar.js"></script>')

The answer Alex Mcmillan provided helped me the most but didn't quite work for a more complex script tag.

I slightly tweaked his answer to come up with a solution for a long tag with various functions that was additionally already setting "src".

(For my use case the script needed to live in head which is reflected here as well):

  componentWillMount () {
      const script = document.createElement("script");

      const scriptText = document.createTextNode("complex script with functions i.e. everything that would go inside the script tags");

      script.appendChild(scriptText);
      document.head.appendChild(script);
  }

You can also use react helmet

import React from "react";
import {Helmet} from "react-helmet";

class Application extends React.Component {
  render () {
    return (
        <div className="application">
            <Helmet>
                <meta charSet="utf-8" />
                <title>My Title</title>
                <link rel="canonical" href="http://example.com/example" />
                <script src="/path/to/resource.js" type="text/javascript" />
            </Helmet>
            ...
        </div>
    );
  }
};

Helmet takes plain HTML tags and outputs plain HTML tags. It's dead simple, and React beginner friendly.


There is a very nice workaround using Range.createContextualFragment.

/**
 * Like React's dangerouslySetInnerHTML, but also with JS evaluation.
 * Usage:
 *   <div ref={setDangerousHtml.bind(null, html)}/>
 */
function setDangerousHtml(html, el) {
    if(el === null) return;
    const range = document.createRange();
    range.selectNodeContents(el);
    range.deleteContents();
    el.appendChild(range.createContextualFragment(html));
}

This works for arbitrary HTML and also retains context information such as document.currentScript.


I created a React component for this specific case: https://github.com/coreyleelarson/react-typekit

Just need to pass in your Typekit Kit ID as a prop and you're good to go.

import React from 'react';
import Typekit from 'react-typekit';

const HtmlLayout = () => (
  <html>
    <body>
      <h1>My Example React Component</h1>
      <Typekit kitId="abc123" />
    </body>
  </html>
);

export default HtmlLayout;

This answer explains the why behind this behavior.

Any approach to render the script tag doesn't work as expected:

  1. Using the script tag for external scripts
  2. Using dangerouslySetInnerHTML

Why

React DOM (the renderer for react on web) uses createElement calls to render JSX into DOM elements.

createElement uses the innerHTML DOM API to finally add these to the DOM (see code in React source). innerHTML does not execute script tag added as a security consideration. And this is the reason why in turn rendering script tags in React doesn't work as expected.

For how to use script tags in React check some other answers on this page.


If you need to have <script> block in SSR (server-side rendering), an approach with componentDidMount will not work.

You can use react-safe library instead. The code in React will be:

import Safe from "react-safe"

// in render 
<Safe.script src="https://use.typekit.net/foobar.js"></Safe.script>
<Safe.script>{
  `try{Typekit.load({ async: true });}catch(e){}`
}
</Safe.script>

According to Alex McMillan's solution, I have the following adaptation.
My own environment: React 16.8+, next v9+

// add a custom component named Script
// hooks/Script.js

import { useEffect } from 'react'

const useScript = (url, async) => {
  useEffect(() => {
    const script = document.createElement('script')

    script.src = url
    script.async = (typeof async === 'undefined' ? true : async )

    document.body.appendChild(script)

    return () => {
      document.body.removeChild(script)
    }
  }, [url])
}

export default function Script({ src, async=true}) {

  useScript(src, async)

  return null  // Return null is necessary for the moment.
}

// Use the custom compoennt, just import it and substitute the old lower case <script> tag with the custom camel case <Script> tag would suffice.
// index.js

import Script from "../hooks/Script";

<Fragment>
  {/* Google Map */}
  <div ref={el => this.el = el} className="gmap"></div>

  {/* Old html script */}
  {/*<script type="text/javascript" src="http://maps.google.com/maps/api/js"></script>*/}

  {/* new custom Script component */}
  <Script src='http://maps.google.com/maps/api/js' async={false} />
</Fragment>

Solution depends on scenario. Like in my case, I had to load a calendly embed inside a react component.

Calendly looks for a div and reads from it's data-url attribute and loads an iframe inside the said div.

It is all good when you first load the page: first, div with data-url is rendered. Then calendly script is added to body. Browser downloads and evaluates it and we all go home happy.

Problem comes when you navigate away and then come back into the page. This time the script is still in body and browser doesn't re-download & re-evaluate it.

Fix:

  1. On componentWillUnmount find and remove the script element. Then on re mount, repeat the above steps.
  2. Enter $.getScript. It is a nifty jquery helper that takes a script URI and a success callback. Once the script it loaded, it evaluates it and fires your success callback. All I have to do is in my componentDidMount $.getScript(url). My render method already has the calendly div. And it works smooth.

I tried to edit the accepted answer by @Alex McMillan but it won't let me so heres a separate answer where your able to get the value of the library your loading in. A very important distinction that people asked for and I needed for my implementation with stripe.js.

useScript.js

import { useState, useEffect } from 'react'

export const useScript = (url, name) => {

  const [lib, setLib] = useState({})

  useEffect(() => {
    const script = document.createElement('script')

    script.src = url
    script.async = true
    script.onload = () => setLib({ [name]: window[name] })

    document.body.appendChild(script)

    return () => {
      document.body.removeChild(script)
    }
  }, [url])

  return lib

}

usage looks like

const PaymentCard = (props) => {
  const { Stripe } = useScript('https://js.stripe.com/v2/', 'Stripe')
}

NOTE: Saving the library inside an object because often times the library is a function and React will execute the function when storing in state to check for changes -- which will break libs (like Stripe) that expect to be called with specific args -- so we store that in an object to hide that from React and protect library functions from being called.


My favorite way is to use React Helmet – it's a component that allows for easy manipulation of the document head in a way you're probably already used to.

e.g.

import React from "react";
import {Helmet} from "react-helmet";

class Application extends React.Component {
  render () {
    return (
        <div className="application">
            <Helmet>
                <script src="https://use.typekit.net/foobar.js"></script>
                <script>try{Typekit.load({ async: true });}catch(e){}</script>
            </Helmet>
            ...
        </div>
    );
  }
};

https://github.com/nfl/react-helmet


for multiple scripts, use this

var loadScript = function(src) {
  var tag = document.createElement('script');
  tag.async = false;
  tag.src = src;
  document.getElementsByTagName('body').appendChild(tag);
}
loadScript('//cdnjs.com/some/library.js')
loadScript('//cdnjs.com/some/other/library.js')

Further to the answers above you can do this:

import React from 'react';

export default class Test extends React.Component {
  constructor(props) {
    super(props);
  }

  componentDidMount() {
    const s = document.createElement('script');
    s.type = 'text/javascript';
    s.async = true;
    s.innerHTML = "document.write('This is output by document.write()!')";
    this.instance.appendChild(s);
  }

  render() {
    return <div ref={el => (this.instance = el)} />;
  }
}

The div is bound to this and the script is injected into it.

Demo can be found on codesandbox.io


You can find best answer at the following link:

https://cleverbeagle.com/blog/articles/tutorial-how-to-load-third-party-scripts-dynamically-in-javascript

const loadDynamicScript = (callback) => {
const existingScript = document.getElementById('scriptId');

if (!existingScript) {
    const script = document.createElement('script');
    script.src = 'url'; // URL for the third-party library being loaded.
    script.id = 'libraryName'; // e.g., googleMaps or stripe
    document.body.appendChild(script);

    script.onload = () => {
      if (callback) callback();
    };
  }

  if (existingScript && callback) callback();
};

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