feat(gatsby-theme-minimal-blog): Lazy load code component

examples/minimal-blog/gatsby-config.js

@@ -54,5 +54,6 @@ module.exports = {
     },
     `gatsby-plugin-offline`,
     `gatsby-plugin-netlify`,
+    // `gatsby-plugin-webpack-bundle-analyser-v2`,
   ],
 }

examples/minimal-blog/package.json

@@ -27,6 +27,7 @@
     "react-dom": "^16.9.0"
   },
   "devDependencies": {
-    "cross-env": "^5.2.0"
+    "cross-env": "^5.2.0",
+    "gatsby-plugin-webpack-bundle-analyser-v2": "^1.1.8"
   }
 }

themes/gatsby-theme-minimal-blog/package.json

@@ -22,6 +22,7 @@
   "dependencies": {
     "@emotion/core": "^10.0.22",
     "@lekoarts/gatsby-theme-minimal-blog-core": "^1.0.1",
+    "@loadable/component": "^5.10.3",
     "@mdx-js/react": "^1.1.5",
     "@theme-ui/color": "^0.2.49",
     "@theme-ui/components": "^0.2.49",

themes/gatsby-theme-minimal-blog/src/components/code.tsx

@@ -1,9 +1,8 @@
 /* eslint react/destructuring-assignment: 0 */
 import React from "react"
-import Highlight, { defaultProps, Language } from "prism-react-renderer"
-import theme from "prism-react-renderer/themes/nightOwl"
-import { LiveProvider, LiveEditor, LiveError, LivePreview } from "react-live"
+import loadable from "@loadable/component"
 import useSiteMetadata from "../hooks/use-site-metadata"
+import { HighlightInnerProps, Language } from "../types"
 
 type CodeProps = {
   codeString: string
@@ -13,6 +12,27 @@ type CodeProps = {
   [key: string]: any
 }
 
+const LazyHighlight = loadable(async () => {
+  const Module = await import(`prism-react-renderer`)
+  const Highlight = Module.default
+  const { defaultProps } = Module
+  return (props: any) => <Highlight {...defaultProps} {...props} />
+})
+
+const LazyLiveProvider = loadable(async () => {
+  const Module = await import(`react-live`)
+  const { LiveProvider, LiveEditor, LiveError, LivePreview } = Module
+  return (props: any) => (
+    <LiveProvider {...props}>
+      <LiveEditor data-name="live-editor" />
+      <LiveError />
+      <LivePreview data-name="live-preview" />
+    </LiveProvider>
+  )
+})
+
+const theme = loadable(() => import(`prism-react-renderer/themes/nightOwl`))
+
 function getParams(className = ``) {
   const [lang = ``, params = ``] = className.split(`:`)
 
@@ -67,17 +87,11 @@ const Code = ({
   const hasLineNumbers = !noLineNumbers && language !== `noLineNumbers` && showLineNumbers
 
   if (props[`react-live`]) {
-    return (
-      <LiveProvider code={codeString} noInline theme={theme}>
-        <LiveEditor data-name="live-editor" />
-        <LiveError />
-        <LivePreview data-name="live-preview" />
-      </LiveProvider>
-    )
+    return <LazyLiveProvider code={codeString} noInline theme={theme} />
   }
   return (
-    <Highlight {...defaultProps} code={codeString} language={language} theme={theme}>
-      {({ className, style, tokens, getLineProps, getTokenProps }) => (
+    <LazyHighlight code={codeString} language={language} theme={theme}>
+      {({ className, style, tokens, getLineProps, getTokenProps }: HighlightInnerProps) => (
         <React.Fragment>
           {title && (
             <div className="code-title">
@@ -106,7 +120,7 @@ const Code = ({
           </div>
         </React.Fragment>
       )}
-    </Highlight>
+    </LazyHighlight>
   )
 }
 

themes/gatsby-theme-minimal-blog/src/index.d.ts

@@ -1,3 +1,4 @@
 declare module "@theme-ui/components"
 declare module "@theme-ui/color"
-declare module "lodash.kebabcase"
+declare module "lodash.kebabcase"
+declare module "@loadable/component"

themes/gatsby-theme-minimal-blog/src/types.d.ts

@@ -0,0 +1,149 @@
+import * as React from "react"
+
+export type Language =
+  | "markup"
+  | "bash"
+  | "clike"
+  | "c"
+  | "cpp"
+  | "css"
+  | "javascript"
+  | "jsx"
+  | "coffeescript"
+  | "actionscript"
+  | "css-extr"
+  | "diff"
+  | "git"
+  | "go"
+  | "graphql"
+  | "handlebars"
+  | "json"
+  | "less"
+  | "makefile"
+  | "markdown"
+  | "objectivec"
+  | "ocaml"
+  | "python"
+  | "reason"
+  | "sass"
+  | "scss"
+  | "sql"
+  | "stylus"
+  | "tsx"
+  | "typescript"
+  | "wasm"
+  | "yaml"
+
+type Token = {
+  types: string[]
+  content: string
+  empty?: boolean
+}
+
+type PrismGrammar = {
+  [key: string]: any
+}
+
+type LanguageDict = { [lang in Language]: PrismGrammar }
+
+type PrismLib = {
+  languages: LanguageDict
+  tokenize: (code: string, grammar: PrismGrammar, language: Language) => PrismToken[] | string[]
+  highlight: (code: string, grammar: PrismGrammar, language: Language) => string
+}
+
+type PrismThemeEntry = {
+  color?: string
+  backgroundColor?: string
+  fontStyle?: "normal" | "italic"
+  fontWeight?: "normal" | "bold" | "100" | "200" | "300" | "400" | "500" | "600" | "700" | "800" | "900"
+  textDecorationLine?: "none" | "underline" | "line-through" | "underline line-through"
+  opacity?: number
+  [styleKey: string]: string | number | void
+}
+
+type PrismTheme = {
+  plain: PrismThemeEntry
+  styles: Array<{
+    types: string[]
+    style: PrismThemeEntry
+    languages?: Language[]
+  }>
+}
+
+type ThemeDict = {
+  root: StyleObj
+  plain: StyleObj
+  [type: string]: StyleObj
+}
+
+type PrismToken = {
+  type: string
+  content: Array<PrismToken | string> | string
+}
+
+type StyleObj = {
+  [key: string]: string | number | null
+}
+
+type LineInputProps = {
+  key?: React.Key
+  style?: StyleObj
+  className?: string
+  line: Token[]
+  [otherProp: string]: any
+}
+
+type LineOutputProps = {
+  key?: React.Key
+  style?: StyleObj
+  className: string
+  [otherProps: string]: any
+}
+
+type TokenInputProps = {
+  key?: React.Key
+  style?: StyleObj
+  className?: string
+  token: Token
+  [otherProp: string]: any
+}
+
+type TokenOutputProps = {
+  key?: React.Key
+  style?: StyleObj
+  className: string
+  children: string
+  [otherProp: string]: any
+}
+
+type RenderProps = {
+  tokens: Token[][]
+  className: string
+  style: StyleObj
+  getLineProps: (input: LineInputProps) => LineOutputProps
+  getTokenProps: (input: TokenInputProps) => TokenOutputProps
+}
+
+type DefaultProps = {
+  Prism: PrismLib
+  theme: PrismTheme
+}
+
+interface HighlightProps {
+  Prism: PrismLib
+  theme?: PrismTheme
+  language: Language
+  code: string
+  children: (props: RenderProps) => React.ReactNode
+}
+
+export interface HighlightInnerProps {
+  className: string
+  style: StyleObj
+  tokens: Token[][]
+  themeDict: ThemeDict
+  getLineProps: (lineInputProps: LineInputProps) => LineOutputProps
+  getStyleForToken: (token: Token) => { [inlineStyle: string]: string }
+  getTokenProps: (tokenInputPropsL: TokenInputProps) => TokenOutputProps
+}