Gatsby descrete notes

Anh-Thi Dinh
Gatsby is "à la mode" and makes us feel that it's really fast. This note was made when I switched from Jekyll to Gatsby. I did not have much experience with React (neither JS) yet. You will find in this note not only things from Gatsby, but also from React and JS.

Installation on localhost

👉 Install npm and NodeJS (with npm). Check NodeJS + npm.
👉 Check
the official doc.
Then install gatsby globally,
1npm install -g gatsby-cli
2# Check version
3gatsby --version
👉 You should use starters, I choose official gatsby-starter-blog for the version 5 of my website.
1npx gatsby new gatsby-starter-blog <>

Some tips for dev locally

1# Restart cache
2gatsby clean
👉 Woring with .env file | Gatsby Official doc.
👉 Note:
Using .env file in a NodeJS project
Troubleshooting common errors | Gatsby Official doc.


  • React / Gatsby use JSX syntax. It's an XML/HTML-like syntax used by React that extends ECMAScript so that XML/HTML-like text can co-exist with JavaScript/React code.
  • Internal URLs: use Link (replaces <a> tag for internal links).
    • ⚠️
      You cannot use target='_blank' with <Link> because whenever you use internal links, they are always in the same window!
  • External URLs: use <a></a> as usual.
  • Use className instead of class=. E.g. className = "abc" or className = "abc xyz".
  • Inline CSS, <div style={{ color: "#ffff", paddingTop: "10px" }}></div>.
  • Date in Gatsby: {new Date().getFullYear()} or using moment.js.

Gatsby structure

  • Recipes -- a cookbook on how to build things, Gatsby style.
👉 Read this to understand the differences between Class Component and Functional Component (a.k.a. stateless). Below are 2 examples which give the same result.
1// Class Component
2class MyComponentClass extends React.Component {
3  render() {
4    return <div>{}</div>;
5  }
1// Functional Component
2const MyStatelessComponent = props => <div>{}</div>;
3// without JSX
4const MyStatelessComponent = props => React.createElement('div', null,;
  • Functional Component (stateless component): just a plain javascript function which takes props as an argument and returns a react element. You can't reach this.state inside it.
  • Component class: has a state, lifecycle hooks and it is a javascript class.
💡 The rule would be: if your component needs some data which cannot be passed as a prop, use class component to get that data. If you need to keep UI state in your component (expandable blocks) so it’s a good place to keep that info in a components state.

Understand props

When React sees an element representing a user-defined component, it passes JSX attributes to this component as a single object. We call this object "props" (properties). (ref)


A page is basically,
1import React from "react"
2function AboutPage(props) {
3  return (
4    <div className="about-container">
5      <p>About me.</p>
6    </div>
7  )
10export default AboutPage
1import React from "react"
2export default (props) => {
3  return (
4    // ...
5  )
8// or
9const AboutPage = (props) => (
10  // ...
12export default AboutPage

Apply Bootstrap

👉 I prefer TailwindCSS for the version 5 of my website. Check next section.

Using TailwindCSS

Using sass

Note: With Tailwind, you nearly don't need to write your own css rules.
1// in /scr/pages/index.js
2import Layout from "../layouts/layout"
1// in /scr/layouts/layout.js
2import "../styles/main.scss"
1// in /scr/styles/main.scss
2@import "layout";
1// in /scr/styles/_layout.scss
2// scss codes

Differences between layouts and templates

These 2 concepts are not the core concepts of Gatby, we just need to use them for a good structure of our project. Their definitions are different, here are mine.
There are 2 separated folders /src/layouts and /src/templates.
  • layouts: usually the blueprint which doesn't contain graphql statements. For example, taxonomy.tsx (a blueprint for all categories, tags pages), base.tsx, page.tsx.
  • templates: "theme" for more specific types which usually contain grapql statements. For example, category.tsx, post.tsx, author.tsx, tag.tsx

Design base layout

What I need in the base layout:
  • A fixed navigation bar on top.
  • A fixed footer on bottom.
  • A flexible header.
  • A body wraper.

Design post / page templates

Their differences are just the width of the container.

Different Header for different page types

1// in src/components/Header.js
2import React, { Component } from 'react'
4export default class Header extends Component {
5  render() {
6    const headerType = this.props.type
7    switch (headerType) {
8      case 'index':
9        return (
10          <>
11            <header className="idx-header header">
12              ...
13            </header>
14          </>
15        )
16      default:
17        return (
18          <>
19            <header className="header">
20              ...
21            </header>
22          </>
23        )
24    }
25  }
1// in src/layouts/base.js
2import Header from "../components/Header"
3const Layout = ({ children, headerType='page' }) => {
4  return (
5    <>
6      <Header type='index' />
7      {children}
8    </>
9  )
11export default Layout
1// in src/pages/index.js
2import Layout from "../layouts/base"
3const IndexPage = () => (
4  <Layout headerType='index'>
5    ...
6  </Layout>
8export default IndexPage

Add Navigation bar

Using react-bootstrap, create a file src/components/Navigation.js whose content is,
1import React from 'react'
2import {Navbar, Nav, NavDropdown, Form, FormControl, Button} from 'react-bootstrap'
4export default (props) => (
5  // the codes from <>
Then, in /src/Header.js
1import Navigation from '../components/Navigation'
3const Header = () => (
4  <header ..>
5    <Navigation></Navigation>
6    // other codes
7  </header>
If you get stuck, check this video.
Install (the free things) (if you have a pro license, read this) or this
1npm i --save @fortawesome/fontawesome-svg-core @fortawesome/react-fontawesome @fortawesome/free-regular-svg-icons @fortawesome/free-solid-svg-icons @fortawesome/free-brands-svg-icons
To import everything in one place instead of importing each icon into each separate file, we'll create a Font Awesome library. Create src/components/fontawesome.js
1// import the library
2import { library } from '@fortawesome/fontawesome-svg-core';
4// import your icons
5import { faHome, faFire, faEdit,  } from '@fortawesome/free-solid-svg-icons';
8  faHome, faFire, faEdit,
Note that, an icon fas fa-money-bill will have name faMoneyBill from free-solid-svg-icons. In the case you wanna import an entire package,
1import { library } from '@fortawesome/fontawesome-svg-core';
2import { fab } from '@fortawesome/free-brands-svg-icons';
In src/pages/index.js (for example),
1import '../components/fontawesome'
2import { FontAwesomeIcon } from '@fortawesome/react-fontawesome'
4<FontAwesomeIcon icon={'home'} /> // for 'faHome' or 'fas fa-home'
5<FontAwesomeIcon icon={['fab', 'github']} /> // for 'faGithub' or `fab fa-github`
💡 Yes! fortawesome is correct!!!
💡 If you have a problem in that the icon is firstly flashing big and then smaller, you need to set the configuration autoAddCss to false, (ref)
1import { config  } from '@fortawesome/fontawesome-svg-core'
2import "@fortawesome/fontawesome-svg-core/styles.css"
3config.autoAddCss = false

Google Fonts

Using typeface.js (search font in npmjs),
1# install
2npm install --save typeface-open-sans
1# in gatsby-browser.js
Rebuild to see the result!
Below is the old method (it didn't work well, it doesn't contain font-weight 600 for Open Sans without reason).
1npm install --save gatsby-plugin-prefetch-google-fonts
1// in /gatsby-config.js
2module.exports = {
3 plugins: [
4    {
5      resolve: `gatsby-plugin-prefetch-google-fonts`,
6      options: {
7        fonts: [
8          {
9            family: `Roboto Mono`,
10            variants: [`400`, `700`]
11          },
12          {
13            family: `Roboto`,
14            subsets: [`latin`]
15          },
16        ],
17      },
18    }
19  ]

Insert images / photos

Adding markdown posts

Posts (.md files) are stored in /content/posts/. Install gatsby-transformer-remark
1npm install --save gatsby-transformer-remark
And add the following to gatsby-config.js
1plugins: [
2  {
3    resolve: `gatsby-source-filesystem`,
4    options: {
5      name: `posts`,
6      path: `${__dirname}/content/posts`,
7    },
8  },
9  `gatsby-transformer-remark`,
10  // there may be already others like this
11  {
12    resolve: `gatsby-source-filesystem`,
13    options: {
14      name: `images`,
15      path: `${__dirname}/src/images`,
16    },
17  },
Create a file called in content/posts/
2path: "/first-post"
3date: "2019-05-04"
4title: "My first blog post"
5--- this and this example for more...

Display site / post info on browser tab

1import Layout from "../layouts/base"
2import Helmet from 'react-helmet'
3const IndexPage = () => (
4  <Layout>
5    <Helmet title={`Thi | I failed my way to success`} />
6  </Layout>

Render html tag in a string

Instead of <p dangerouslySetInnerHTML={{ headerIntro }} />, you can use <p dangerouslySetInnerHTML={{__html: headerIntro }} />. If there is a html tag in headerIntro, e.g. "<i>Hello</i>" will be rendered as Hello.

JSX in Markdown

  • Download and use MDX plugin.
  • We have to put all mdx files in /src/pages. The mdx files will be renders automatically! That's why we need to indicate defaultLayouts in /gatsby-config.js (ref). I have tried to render mdx in /content/pages/ but it didn't work!
  • For an example of using graphql in mdx file, check /src/pages/about.mdx.
  • For a specific page, one can use props.pageContext.frontmatter.title to take the title of that page.
  • For writing pages, read this.

Create page template and markdown file

Suppose that you wanna create a page /about taking content from file /content/pages/ and it applies template /src/templates/page.js. All you need to do is following this post.
  1. First, add to /gatsby-config.
  1. Create /src/templates/page.js
  1. Create markdown file /content/pages/
  1. Modify /gatsby-node.js to tell gatsby to create a page /about from using template page.js.


👉 Requires...
1# [email protected] requires a peer of [email protected]
2npm i [email protected] --save
4# [email protected] requires a peer of typescript@>=2.8.0
5npm i typescript --save
👉 Cannot read property...
1# TypeError: Cannot read property 'fileName' of undefined
Above error comes from inserting images using query. To overcome this, we have to use StaticQuery which is introduced in Gatsby v2 (I don't know why it works!?) 👉 The reason is that the (old) page query can only be added to page components (in my try, I add in Header.js component). StaticQuery can be used as a replacement of page query, it can be added to any component. (ref)
👉 Fail to build on Netlify Build script returned non-zero exit code: 127
  • Delete package-lock.json, don't include it and node_modules on git.
  • Remove either package.json or yarn.lock on Github (remove yarn).
  • "version": "0.1", is wrong, changing to "1.0.1" is OK.
👉 Fail to build on Netlify Can't resolve '../components/Header' in '/opt/build/repo/src/components' for examples. 👉 The problem comes from the original name of file Header.js is header.js. I renamed it to Header.js but it's still actually header.js (check the Github Desktop to see). You can change is to HeaderNew.js to fix the problem!
👉 If you wanna use adjacent react components, you have to put them inside <>..</> (React fragment) like below example,
1return (
2    <>
3      <Navigation></Navigation>
4      <Header type={headerType} />
5      <span>Thi</span>
6    </>
7  )
This allows you to return multiple child components without appending additional nodes to the DOM.
👉 Warning: Each child in a list should have a unique "key" prop. You have to make sure that each child of a list in react component has a unique key. For example
1// error
2{ => (
3  <>
4    <span key={}> Thi </span>
5    <Link key={}> {} </Link>
6  </>
1// but this
2{ => (
3  <span key={}>
4    <span> Thi </span>
5    <Link> {} </Link>
6  </>