Enable caching publish directory

helpers/incremental/caching.js

@@ -1,7 +1,17 @@
-import { promises as fs } from 'fs'
+import path from 'path'
 
 import { default as TOML } from '@iarna/toml'
+// https://github.com/jprichardson/node-fs-extra
+import fs from 'fs-extra'
 
+import { isProduction, rootDir } from '../environment.js'
+
+
+
+// https://github.com/hanbyul-here/nuxt-incremental-build-exp/blob/cb3ef6b001b283de77efee64733db273d991129b/cache-me.js
+export const CACHE_PATH = isProduction
+    ? path.join('/', 'opt', 'build', 'cache', 'app_build') // Netlify cache path
+    : path.join(rootDir, '.app_build_cache')//path.resolve(__dirname, '.app_build_cache')
 
 
 export async function getNetlifyConfig () {
@@ -11,3 +21,39 @@ export async function getNetlifyConfig () {
 
     return TOML.parse( netlifyTomlContents )
 }
+
+
+export async function getPublishDirectoryName () {
+    const netlifyConfig = await getNetlifyConfig()
+
+    return netlifyConfig.build.publish
+}
+
+
+export async function getPublishDirectoryPath () {
+    const publishDirectoryPath = await getPublishDirectoryName()
+
+    return path.resolve( rootDir, publishDirectoryPath )
+}
+
+
+export async function hasCachedPublishFolder () {
+    const homePageFile = `${ CACHE_PATH }/index.html`
+
+    // https://github.com/jprichardson/node-fs-extra/blob/master/docs/pathExists.md
+    return await fs.pathExists( homePageFile )
+}
+
+
+export async function cachePublishFolder () {
+
+    const publishDirectoryPath = await getPublishDirectoryPath()
+
+    console.log('publishDirectoryPath', publishDirectoryPath)
+
+    // Make sure cache folder exists
+    await fs.ensureDir( CACHE_PATH )
+
+    await fs.copy( publishDirectoryPath, CACHE_PATH )
+
+}

helpers/incremental/caching.test.js

@@ -1,7 +1,11 @@
 import test from 'ava'
 
 import { isObject, isString } from '../type-checks.js'
-import { getNetlifyConfig } from './caching.js'
+import {
+    getNetlifyConfig,
+    hasCachedPublishFolder,
+    cachePublishFolder
+} from './caching.js'
 
 
 test('Can read netlify.toml', async (t) => {
@@ -15,8 +19,30 @@ test('Can read netlify.toml', async (t) => {
     t.is( isString( netlifyConfig.build.publish ) , true )
 })
 
-// test('Can cache publish folder', async (t) => {
+
+test('Can cache publish folder', async (t) => {
+    // So that we don't overwrite the cached files
+    // we check if a cached file already exists
+
+    if ( await hasCachedPublishFolder() ) {
+        t.log('Publish folder has been cached already')
+        t.pass()
+    }
+
+    t.log('No prexisting cache folder found')
+
+
+    // If there's no files there already
+    // then we can write to the directory with
+    await cachePublishFolder()
 
 
 
-// })
+    if ( (await hasCachedPublishFolder()) === false ) {
+        t.fail()
+        return
+    }
+
+    t.log('Publish folder has been cached already')
+    t.pass()
+})