From 27120fdcf2531ea13dab74ffd6e61aa87e774a02 Mon Sep 17 00:00:00 2001
From: Damien Senger <damien.senger@castoredc.com>
Date: Thu, 23 Apr 2020 22:29:55 +0200
Subject: [PATCH] chore(gatsby): Migrate utils/page-data to TypeScript

This commit migrates the existing `src/utils/page-data.ts` file to
TypeScript by trying to stick as close as possible to the original
JavaScript file.

To take advantage of existing Redux typings, I tried to extend the
typings from the `IGatsbyPage` interface describing page data.
---
 packages/gatsby/src/utils/page-data.js | 52 -----------------
 packages/gatsby/src/utils/page-data.ts | 79 ++++++++++++++++++++++++++
 2 files changed, 79 insertions(+), 52 deletions(-)
 delete mode 100644 packages/gatsby/src/utils/page-data.js
 create mode 100644 packages/gatsby/src/utils/page-data.ts

diff --git a/packages/gatsby/src/utils/page-data.js b/packages/gatsby/src/utils/page-data.js
deleted file mode 100644
index 374bdae1df472..0000000000000
--- a/packages/gatsby/src/utils/page-data.js
+++ /dev/null
@@ -1,52 +0,0 @@
-const fs = require(`fs-extra`)
-const path = require(`path`)
-const { store } = require(`../redux`)
-
-const fixedPagePath = pagePath => (pagePath === `/` ? `index` : pagePath)
-
-const getFilePath = ({ publicDir }, pagePath) =>
-  path.join(publicDir, `page-data`, fixedPagePath(pagePath), `page-data.json`)
-
-const read = async ({ publicDir }, pagePath) => {
-  const filePath = getFilePath({ publicDir }, pagePath)
-  const rawPageData = await fs.readFile(filePath, `utf-8`)
-  return JSON.parse(rawPageData)
-}
-
-const remove = async ({ publicDir }, pagePath) => {
-  const filePath = getFilePath({ publicDir }, pagePath)
-  if (fs.existsSync(filePath)) {
-    return await fs.remove(filePath)
-  }
-  return Promise.resolve()
-}
-
-const write = async ({ publicDir }, page, result) => {
-  const filePath = getFilePath({ publicDir }, page.path)
-  const body = {
-    componentChunkName: page.componentChunkName,
-    path: page.path,
-    matchPath: page.matchPath,
-    result,
-  }
-  const bodyStr = JSON.stringify(body)
-  // transform asset size to kB (from bytes) to fit 64 bit to numbers
-  const pageDataSize = Buffer.byteLength(bodyStr) / 1000
-
-  store.dispatch({
-    type: `ADD_PAGE_DATA_STATS`,
-    payload: {
-      filePath,
-      size: pageDataSize,
-    },
-  })
-
-  await fs.outputFile(filePath, bodyStr)
-}
-
-module.exports = {
-  read,
-  write,
-  remove,
-  fixedPagePath,
-}
diff --git a/packages/gatsby/src/utils/page-data.ts b/packages/gatsby/src/utils/page-data.ts
new file mode 100644
index 0000000000000..b4294c11846ff
--- /dev/null
+++ b/packages/gatsby/src/utils/page-data.ts
@@ -0,0 +1,79 @@
+import fs from "fs-extra"
+import path from "path"
+import { IGatsbyPage } from "../redux/types"
+import { store } from "../redux"
+
+interface IPageDataContext {
+  publicDir: string
+}
+
+interface IPageData
+  extends Pick<IGatsbyPage, "componentChunkName" | "matchPath" | "path"> {
+  result: any
+}
+
+export const fixedPagePath = (pagePath: string): string =>
+  pagePath === `/` ? `index` : pagePath
+
+const getFilePath = (
+  { publicDir }: IPageDataContext,
+  pagePath: string
+): string =>
+  path.join(publicDir, `page-data`, fixedPagePath(pagePath), `page-data.json`)
+
+export const read = async (
+  { publicDir }: IPageDataContext,
+  pagePath: string
+): Promise<IPageData> => {
+  const filePath = getFilePath({ publicDir }, pagePath)
+  const rawPageData = await fs.readFile(filePath, `utf-8`)
+
+  return JSON.parse(rawPageData)
+}
+
+export const remove = async (
+  { publicDir }: IPageDataContext,
+  pagePath: string
+): Promise<void> => {
+  const filePath = getFilePath({ publicDir }, pagePath)
+
+  if (fs.existsSync(filePath)) {
+    return await fs.remove(filePath)
+  }
+
+  return Promise.resolve()
+}
+
+export const write = async (
+  { publicDir }: IPageDataContext,
+  { componentChunkName, matchPath, path }: Exclude<IPageData, "result">,
+  result: IPageData["result"]
+): Promise<void> => {
+  const filePath = getFilePath({ publicDir }, path)
+  const body = {
+    componentChunkName,
+    path,
+    matchPath,
+    result,
+  }
+  const bodyStr = JSON.stringify(body)
+  // transform asset size to kB (from bytes) to fit 64 bit to numbers
+  const pageDataSize = Buffer.byteLength(bodyStr) / 1000
+
+  store.dispatch({
+    type: `ADD_PAGE_DATA_STATS`,
+    payload: {
+      filePath,
+      size: pageDataSize,
+    },
+  })
+
+  await fs.outputFile(filePath, bodyStr)
+}
+
+export default {
+  fixedPagePath,
+  read,
+  remove,
+  write,
+}