Scripts? about react-head

[wmertens]

The use case is both inline and linked scripts. The most important thing is that the scripts should only execute once when already rendered via SSR. I suppose checking the contents would be sufficient to ward against this?

Here's how I load ga:

/* global __PRODUCTION__ __CLIENT__ __CONFIG__ */
import React, {Fragment} from 'react'
import Helmet from 'react-helmet'
import {LocationListener} from 'plugins/react-router-deluxe'

const {gaId, gAdwordsId} = __CONFIG__

export const gtag = (...args) => global.gtag && global.gtag(...args)

const handlePageView = location =>
	gtag('config', gaId, {
		// eslint-disable-next-line camelcase
		page_path: location.pathname + location.search,
	})

// Don't render the scripts on the client, they
// should be loaded on initial html only
// Also https://github.com/nfl/react-helmet/issues/357
const GoogleAnalytics = () =>
	__CLIENT__ ? (
		<LocationListener onChange={handlePageView} />
	) : __PRODUCTION__ && gaId ? (
		<Fragment>
			<Helmet>
				{/* Putting in head because it also offers page speed tracking */}
				<script
					async
					src={`https://www.googletagmanager.com/gtag/js?id=${gaId}`}
				/>
				<script>
					{// Must be string to prevent React from messing with the code
					`window.dataLayer=window.dataLayer||[];function gtag(){dataLayer.push(arguments);}gtag('js',new Date());gtag('config','${gaId}');${
						gAdwordsId ? `gtag('config','${gAdwordsId}');` : ''
					}`}
				</script>
			</Helmet>
		</Fragment>
	) : (
		false
	)

export default GoogleAnalytics

and then I can just put <GoogleAnalytics /> somewhere on the page and it will take care of the rest. The globals are added by webpack.

I think this might also be useful on the client for when you need a third-party library: put a <Script src="url" onLoad={this.handleLibLoaded}/> in the component and react-head makes sure it's loaded only once, but new onLoads are called every time?

[RichiCoder1]

@tizmagik Would you still be game to take a PR on this? I might be interested.

[wmertens]

Oh and for external scripts, caching will indeed prevent downloads, but it will still run the script every time. Most scripts already protect against that, so no big issue, and I can't think of workarounds that always work and don't impact preloading etc.

[TrySound]

react-head will load it twice too. It's better to use another way of loading for scripts IMO.

@tizmagik What do you think?

[wmertens]

It is very nice to be able to specify head content without having to special case it in the SSR renderer - then the renderer can be a package and your project has less code.

[tizmagik]

Interesting! I think maybe we could figure out a way to support this, either by no-op’ing on the server or no-op’ing on the client perhaps?

@wmertens is your use case for inline scripts or linked scripts, or both? If you have a specific use case or some sample code snippets or something you could share that would be helpful to understand the specific use case better.

Will play around with some ideas and post back when I get a chance.

[tizmagik]

@RichiCoder1 — yea for sure, if you’re up for it! Thanks in advance 🙏

[cmmartin]

I'm also looking for this functionality and willing to contribute, but I'm not sure the solution to the double load.

For external scripts, caching should make it irrelevant, right?

Inlined scripts are problematic though. We can't not render them on the client or they won't be set when people navigate in the client. Maybe the server could pass some data to the window indicating an inline script is already loaded?

[wmertens]

Inline scripts could be wrapped with something that makes sure they only run once, but that seems hard to do.
Alternatively, tell the user is up to them to handle that.

[cameronbraid]

Another use case for script tag is to support <script type="application/ld+json">.

Is there a need to special case these, or can a Script head tag component be exposed for this purpose ?

[cameronbraid]

For <script type="application/ld+json"> use case I added a Script tag in #115