feat(js): add list of tree shakable external dependencies

.gitignore

@@ -7,3 +7,4 @@ zip-it-and-ship-it*
 .nyc_output
 coverage
 .eslintcache
+.vscode

src/dependencies.js

@@ -47,7 +47,7 @@ const getDependencies = async function(mainFile, srcDir) {
   const packageRoot = await pkgDir(srcDir)
   const packageJson = getPackageJson(packageRoot)
 
-  const state = { localFiles: [], modulePaths: [] }
+  const state = { localFiles: new Set(), modulePaths: new Set() }
 
   try {
     return await getFileDependencies(mainFile, packageJson, state)
@@ -71,11 +71,11 @@ const getPackageJson = function(packageRoot) {
 }
 
 const getFileDependencies = async function(path, packageJson, state) {
-  if (state.localFiles.includes(path)) {
+  if (state.localFiles.has(path)) {
     return []
   }
 
-  state.localFiles.push(path)
+  state.localFiles.add(path)
 
   const basedir = dirname(path)
   // This parses JavaScript in `path` to retrieve all the `require()` statements
@@ -92,25 +92,64 @@ const getFileDependencies = async function(path, packageJson, state) {
 // `require()` statements can be either `require('moduleName')` or
 // `require(path)`
 const getImportDependencies = function(dependency, basedir, packageJson, state) {
-  if (LOCAL_IMPORT_REGEXP.test(dependency)) {
-    return getLocalImportDependencies(dependency, basedir, packageJson, state)
+  if (LOCAL_IMPORT_REGEXP.test(dependency) || isTreeShakable(dependency)) {
+    return getTreeShakedDependencies(dependency, basedir, packageJson, state)
   }
 
-  return getModuleDependencies(dependency, basedir, state, packageJson)
+  return getAllDependencies(dependency, basedir, state, packageJson)
 }
 
 const LOCAL_IMPORT_REGEXP = /^(\.|\/)/
 
+const isTreeShakable = function(dependency) {
+  if (dependency.includes('next') && !TREE_SHAKABLE_DEPENDENCIES.has(dependency)) {
+    console.log(dependency)
+  }
+  return TREE_SHAKABLE_DEPENDENCIES.has(dependency)
+}
+
+const TREE_SHAKABLE_DEPENDENCIES = new Set([
+  '@next/env',
+  'next/dist/compiled/chalk',
+  'next/dist/compiled/content-type',
+  'next/dist/compiled/cookie',
+  'next/dist/compiled/escape-string-regexp',
+  'next/dist/compiled/etag',
+  'next/dist/compiled/fresh',
+  'next/dist/compiled/jsonwebtoken',
+  'next/dist/compiled/node-fetch',
+  'next/dist/compiled/path-to-regexp',
+  'next/dist/compiled/raw-body',
+  'next/dist/compiled/semver',
+  'next/dist/next-server/lib/constants',
+  'next/dist/next-server/lib/constants.js',
+  'next/dist/next-server/lib/document-context.js',
+  'next/dist/next-server/lib/head.js',
+  'next/dist/next-server/lib/i18n/normalize-locale-path',
+  'next/dist/next-server/lib/router/utils/get-route-from-asset-path',
+  'next/dist/next-server/lib/router/utils/path-match',
+  'next/dist/next-server/lib/router/utils/prepare-destination',
+  'next/dist/next-server/lib/utils',
+  'next/dist/next-server/lib/utils.js',
+  'next/dist/next-server/server/api-utils',
+  'next/dist/next-server/server/denormalize-page-path',
+  'next/dist/next-server/server/get-page-files.js',
+  'next/dist/next-server/server/node-polyfill-fetch',
+  'next/dist/next-server/server/render',
+  'next/dist/next-server/server/send-payload',
+  'next/dist/next-server/server/utils.js'
+])
+
 // When a file requires another one, we apply the top-level logic recursively
-const getLocalImportDependencies = async function(dependency, basedir, packageJson, state) {
+const getTreeShakedDependencies = async function(dependency, basedir, packageJson, state) {
   const dependencyPath = await resolvePathPreserveSymlinks(dependency, basedir)
   const depsPath = await getFileDependencies(dependencyPath, packageJson, state)
   return [dependencyPath, ...depsPath]
 }
 
 // When a file requires a module, we find its path inside `node_modules` and
 // use all its published files. We also recurse on the module's dependencies.
-const getModuleDependencies = async function(dependency, basedir, state, packageJson) {
+const getAllDependencies = async function(dependency, basedir, state, packageJson) {
   const moduleName = getModuleName(dependency)
 
   // Happens when doing require("@scope") (not "@scope/name") or other oddities
@@ -150,11 +189,11 @@ const getModuleNameDependencies = async function(moduleName, basedir, state) {
 
   const modulePath = dirname(packagePath)
 
-  if (state.modulePaths.includes(modulePath)) {
+  if (state.modulePaths.has(modulePath)) {
     return []
   }
 
-  state.modulePaths.push(modulePath)
+  state.modulePaths.add(modulePath)
 
   const pkg = require(packagePath)
 
@@ -223,7 +262,7 @@ const getNestedModules = async function(modulePath, state, pkg) {
   const dependencies = getNestedDependencies(pkg)
 
   const depsPaths = await Promise.all(
-    dependencies.map(dependency => getModuleDependencies(dependency, modulePath, state, pkg))
+    dependencies.map(dependency => getAllDependencies(dependency, modulePath, state, pkg))
   )
   return [].concat(...depsPaths)
 }