react-hydratable
v1.5.0
Published
hold-on DOM structure for improving React SEO
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react-hydratable
react-hydratable
is nodejs module for improving SEO performance of SPA project.
In React, npm run build
create build outputs.
But index.html
has just blank body. Because in SPA framework(ex: react) javascript file will render html elements.
In SPA with CSR, SEO performance is very poor. Of course, SSR framework(ex: nextjs) can solve this problem, but some project cannot be moved from CSR to SSR because of various problems.
In this case, react-hydratable
can be very powerful weapon.
react-hydratable
just create simple http webserver based on your SPA build output, and starting crawling html after executing javascript. Finally crawled html data is saved to appropriate build path.
So, After executing react-hydratable
, index.html
is prerendered.
It has fullfilled body.
Now every search bot(that cannot execute javascript, just read html file) can collect your website informations!!
Installation
install module from npm
npm install -D react-hydratable
setup Go to your project root and open
src/index.js
//react 16, 17 import React from 'react'; import { hydrate, render } from 'react-dom'; // ... //update here //optional render/hydrate if (rootElement.hasChildNodes()) { hydrate(element, rootElement); } else { render(element, rootElement); }
//react 18 import React from "react"; import { createRoot, hydrateRoot } from "react-dom/client"; if (rootElement.hasChildNodes()){ hydrateRoot(rootElement, element); } else { const root = createRoot(rootElement); root.render(element, rootElement); }
If user access crawled page, ???/html
has been filled body. So browser need not break all DOM and re-render all elements.
Browser can use already-made-DOM objects. hydrate()/hydrateRoot()
function support this.
That's all! react-hydratable
is ready!!
Start Crawling
react-hydratable
use /build
files.
Add react-hydratable
script to your package.json
.
package.json
{
"...": "...",
"scripts": {
"...": "...",
//add new scripts
"postbuild": "react-hydratable"
},
"...": "..."
}
This script(postbuild) means that run react-hydratable
after build
script is finished.
What a so simple usage.
You just type npm run build
to terminal.
react-hydratable
will be executed automatically after building project.
Preview prerendered pages
Do you wonder your prerendered pages are working correctly?
react-hydratable
support "preview mode".
// package.json
{
"...": "...",
"scripts": {
"...": "...",
//add new scripts
"preview": "react-hydratable --preview"
},
"...": "..."
}
Now, you can check your prerendered pages after type npm run preview
to terminal.
(Optional) Customize configurations
react-hydratable has default config.
{
"webroot": "./build",
"host": "http://localhost",
"port": 3000,
"crawlingUrls": ["/"],
"delay": 1500,
"htmlPrefix": "<!DOCTYPE html>"
}
If you want customize settings(ex: I want to crawl html about more url), create hydratable.config.json
to project root(same level with package.json
).
Explaination of all configurations is at page bottom.
Set crawling targets(urls)
//hydratable.config.json
{
"crawlingUrls": ["/", "/copyrights"]
}
As this configuration, react-hydratable
start crawling '/' and '/copyrights'.
And also, create new html file(build/copyrights/index.html
) and refresh default index.html file(build/index.html
).
Default crawlingUrls
value is ['/']
(only crawling /build/index.html
and refresh it)
Keep in mind "all type of crawlingUrl must be text/html"
Other Content-Type is not accepted
Set crawling delay
In crawling phase, load html and wait for delay
.
After finishing loading, maybe html
is not perfecttly loadded.
For example, if target page uses ajax
, html
is not perfect before ajax
is finished.
So react-hydratable
solve this problem as waiting some time.
Default waiting time is 1500
ms.
If you want increase delay from 1500ms to 2000ms, override delay
property.
hydratable.config.json
{
"delay": 2000
}
Now react-hydratable
wait 2000 ms after loading page.
Set multi-page crawling
If you have a lot of page that will be crawling(crawlingUrls), it takes many time.
In this case, you can use multi-page crawling.
Default value is 1, this means one page(one window) is used to crawl your crawlingUrls
.
You can increase page(window) count as increase pageCount
value.
But if pageCount
gets too big, server may be slow and also crawling result be wrong.
Recommend set between 1~4.
All configurations
{
"webroot": "/your_project_root/build",
"host": "http://localhost",
"port": 3000,
"crawlingUrls": ["/"],
"delay": 1500,
"userAgent": "react-hydratable",
"htmlPrefix": "<!DOCTYPE html>",
"pageCount": 1,
"retryCount": 1,
}
webroot
: react build directory path
host
: webserver host (http only)
port
: webserver port
crawlingUrls
: crawling target url list
delay
: wait time(ms) after page is loaded
userAgent
: crawler user-agent (request header)
htmlPrefix
: prefix string that is added crawling result (if blank, <!DOCTYPE html>
is not included)
pageCount
: multi-page crawling is support. if you increase this value, crawling speed is up, but may stress to server.
retryCount
: if crawling is fail, do retry as retryCount times automatically.