How to include local javascript on a Gatsby page?

I'm a total React newbie and I guess there is something fundamental I don't quite understand here. A default Gatsby page looks like this. Is there a way to use a local .js file somewhat like this?

<script src="../script/script.js"></script>

What I would like to achieve is to have react ignore script.js but still have the client side use it. A default Gatsby page looks like this, is it possible to do somerthing like that there?

import React from "react"
import { Link } from "gatsby"

import Layout from "../components/layout"
import Image from "../components/image"
import SEO from "../components/seo"

const IndexPage = () => (
  <Layout>
    <SEO title="Home" keywords={[`gatsby`, `application`, `react`]} />
    <h1>Hi people</h1>
    <p>Welcome to your new Gatsby site.</p>
    <p>Now go build something great.</p>
    <div style={{ maxWidth: `300px`, marginBottom: `1.45rem` }}>
      <Image />
    </div>
    <Link to="/page-2/">Go to page 2</Link>
  </Layout>
)

After several hours of frustration I finally stumbled upon discussion on GitHub that solved this for me. In Gatsby, there is a thing called static folder, for which one use case is including a small script outside of the bundled code.

Anyone else in the same situation, try proceeding as follows:

Create a folder static to the root of your project.
Put your script script.js in the folder static.
Include the script in your react dom with react-helmet.

So in the case of the code I posted in my original question, for instance:

import React from "react"
import Helmet from "react-helmet"
import { withPrefix, Link } from "gatsby"

import Layout from "../components/layout"
import Image from "../components/image"
import SEO from "../components/seo"

const IndexPage = () => (
  <Layout>
    <Helmet>
        <script src={withPrefix('script.js')} type="text/javascript" />
    </Helmet>
    <SEO title="Home" keywords={[`gatsby`, `application`, `react`]} />
    <h1>Hi people</h1>
    <p>Welcome to your new Gatsby site.</p>
    <p>Now go build something great.</p>
    <div style={{ maxWidth: `300px`, marginBottom: `1.45rem` }}>
      <Image />
    </div>
    <Link to="/page-2/">Go to page 2</Link>
  </Layout>
)

Notice the imports

import Helmet from "react-helmet"
import { withPrefix, Link } from "gatsby"

and the script element.

<Helmet>
    <script src={withPrefix('script.js')} type="text/javascript" />
</Helmet>

This would have saved hours of my time, hopefully this does it for someone else.

React works with dynamic DOM. But for rendering it by browser, your web server should send a static index page, where React will be included as another script tag.

So, take a look on your index.html page, which you can find in public folder. There you could insert your script tag in the header section, for example.

Gatsby uses html.js in the src folder. Not index.html like most react projects.

Example html.js file:

import React from "react"
import PropTypes from "prop-types"

export default class HTML extends React.Component {
  render() {
    return (
      <html {...this.props.htmlAttributes}>
        <head>
          <meta charSet="utf-8" />
          <meta httpEquiv="x-ua-compatible" content="ie=edge" />
          <meta
            name="viewport"
            content="width=device-width, initial-scale=1, shrink-to-fit=no"
          />
          {this.props.headComponents}
        </head>
        <body {...this.props.bodyAttributes}>
          {this.props.preBodyComponents}
          <div
            key={`body`}
            id="___gatsby"
            dangerouslySetInnerHTML={{ __html: this.props.body }}
          />
          {this.props.postBodyComponents}
        </body>
      </html>
    )
  }
}

HTML.propTypes = {
  htmlAttributes: PropTypes.object,
  headComponents: PropTypes.array,
  bodyAttributes: PropTypes.object,
  preBodyComponents: PropTypes.array,
  body: PropTypes.string,
  postBodyComponents: PropTypes.array,
}

For adding custom Javascript using dangerouslySetInnerHTML inside src/html.js:

<script
  dangerouslySetInnerHTML={{
    __html: `
            var name = 'world';
            console.log('Hello ' + name);
        `,
  }}
/>

You can try adding your js there but, note that your js may not work as expected. You can always look into react-helmet for more dynamic apps and adding scripts to <head>.

Gatsby Documentation: https://www.gatsbyjs.org/docs/custom-html/

来源：https://stackoverflow.com/questions/54834930/how-to-include-local-javascript-on-a-gatsby-page

标签

javascript

reactjs

gatsby