From 06a86cf0dc9c1a2cb588f7424cc05731ba8ff74d Mon Sep 17 00:00:00 2001
From: Egor <eprincev.egor@ya.ru>
Date: Wed, 3 May 2023 19:47:19 +0300
Subject: [PATCH] Support AMD imports with baseUrl and without paths in ts
 config

---
 src/index.ts       | 30 ++++++++++++++++++++++++------
 test/index.test.ts | 22 ++++++++++++++++++++--
 2 files changed, 44 insertions(+), 8 deletions(-)

diff --git a/src/index.ts b/src/index.ts
index 5bf7fb6..d730dba 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,6 +1,8 @@
 import path from 'path'
 import { TransformCallback, Transform } from 'stream'
 import ts from 'typescript'
+import fs from 'fs'
+import { builtinModules } from 'module'
 
 import File = require('vinyl')
 
@@ -42,12 +44,15 @@ function findImports(line: string): string[] | null {
 function resolveImports(
   file: ReadonlyArray<string>,
   imports: FileData[],
-  options: ts.CompilerOptions
+  options: ts.CompilerOptions,
+  nodeModules: string[]
 ): string[] {
   const { baseUrl, paths, cwd } = options
 
+  const base = path.join(cwd as string, path.relative(cwd as string, baseUrl || './'))
+
   const aliases: { [key: string]: string[] | undefined } = {}
-  for (const alias in paths) {
+  for (const alias in paths || {}) {
     /* istanbul ignore else  */
     if (paths.hasOwnProperty(alias)) {
       let resolved = alias
@@ -82,11 +87,17 @@ function resolveImports(
       }
     }
 
+    if (resolved.length < 1 && /^\w/.test(imported.import) && !paths) {
+      const dirName = imported.import.split('/')[0]
+      if (!nodeModules.includes(dirName) && !builtinModules.includes(dirName)) {
+        resolved = path.join(base, './' + imported.import)
+      }
+    }
+
     if (resolved.length < 1) {
       continue
     }
 
-    const base = path.join(cwd as string, path.relative(cwd as string, baseUrl || './'))
     const current = path.relative(base, path.dirname(imported.path))
     const target = path.relative(base, resolved)
 
@@ -133,14 +144,21 @@ const alias: AliasPlugin = ({ config, cwd }: PluginOptions) => {
 
   const compilerOptions = resolveConfig(config, cwd)
 
-  if (!compilerOptions.paths) {
-    throw new Error("Unable to find the 'paths' property in the supplied configuration!")
+  if (!compilerOptions.paths && !compilerOptions.baseUrl) {
+    throw new Error(
+      "Unable to find the 'paths' or 'baseUrl' property in the supplied configuration!"
+    )
   }
 
   if (compilerOptions.baseUrl === undefined || compilerOptions.baseUrl === '.') {
     compilerOptions.baseUrl = './'
   }
 
+  let nodeModules: string[] = []
+  if (!compilerOptions.paths && compilerOptions.baseUrl) {
+    nodeModules = fs.readdirSync(path.join(cwd, 'node_modules'))
+  }
+
   compilerOptions.cwd = cwd
 
   return new Transform({
@@ -168,7 +186,7 @@ const alias: AliasPlugin = ({ config, cwd }: PluginOptions) => {
         return callback(undefined, file)
       }
 
-      const resolved = resolveImports(lines, imports, compilerOptions)
+      const resolved = resolveImports(lines, imports, compilerOptions, nodeModules)
 
       file.contents = Buffer.from(resolved.join('\n'))
 
diff --git a/test/index.test.ts b/test/index.test.ts
index f055ca1..19c82fb 100644
--- a/test/index.test.ts
+++ b/test/index.test.ts
@@ -134,9 +134,9 @@ const tests: Record<string, Test> = {
     error: "Could not find a valid 'tsconfig.json'",
   },
   ["should error with no 'paths' in config"]: {
-    options: { config: { ...config, paths: undefined } },
+    options: { config: { paths: undefined, baseUrl: undefined } },
     path: './src/pages/Page.ts',
-    error: "Unable to find the 'paths' property in the supplied configuration!",
+    error: "Unable to find the 'paths' or 'baseUrl' property in the supplied configuration!",
   },
   ["should error with no 'path' supplied"]: {
     options: { config },
@@ -145,6 +145,24 @@ const tests: Record<string, Test> = {
     output: '',
     error: 'Received file with no path. Files must have path to be resolved.',
   },
+  ['should replace to relative path when config with baseUrl but without Paths']: {
+    options: { config: { baseUrl: './src' } },
+    path: './src/pages/Page.ts',
+    input: "import {Grid} from 'components/grid'",
+    output: "import {Grid} from '../components/grid'",
+  },
+  ['should ignore node module']: {
+    options: { config: { baseUrl: './src' } },
+    path: './src/pages/Page.ts',
+    input: "import File from 'vinyl'",
+    output: "import File from 'vinyl'",
+  },
+  ['should ignore builtin module']: {
+    options: { config: { baseUrl: './src' } },
+    path: './src/pages/Page.ts',
+    input: "import assert from 'assert'",
+    output: "import assert from 'assert'",
+  },
 }
 
 const run = async (test: Test): Promise<void> => {