From e42e7c808b59d6f8c676d6dfc0456294c5da77aa Mon Sep 17 00:00:00 2001
From: JohnGrisham <jgrisham@vhtcx.com>
Date: Fri, 1 Dec 2023 16:15:36 -0600
Subject: [PATCH] feat(resolveExtensions): added stripResolveExtensions option
 to remove file extension prefixes

---
 src/helper.ts            | 17 ++++++++++++++++-
 src/pack.ts              | 13 +++++++++++--
 src/tests/helper.test.ts | 16 ++++++++++++++--
 src/types.ts             |  1 +
 4 files changed, 42 insertions(+), 5 deletions(-)

diff --git a/src/helper.ts b/src/helper.ts
index c0fee898..624475d4 100644
--- a/src/helper.ts
+++ b/src/helper.ts
@@ -9,7 +9,7 @@ import { uniq } from 'ramda';
 
 import type Serverless from 'serverless';
 import type ServerlessPlugin from 'serverless/classes/Plugin';
-import type { Configuration, DependencyMap, FunctionEntry } from './types';
+import type { Configuration, DependencyMap, FunctionEntry, IFile } from './types';
 import type { EsbuildFunctionDefinitionHandler } from './types';
 import { DEFAULT_EXTENSIONS } from './constants';
 
@@ -315,3 +315,18 @@ export const buildServerlessV3LoggerFromLegacyLogger = (
   verbose: legacyLogger.log.bind(legacyLogger),
   success: legacyLogger.log.bind(legacyLogger),
 });
+
+export const stripResolveExtensions = (file: IFile, extensions: string[]): IFile => {
+  const resolveExtensionMatch = file.localPath.match(extensions.map((ext) => ext).join('|'));
+
+  if (resolveExtensionMatch?.length && !DEFAULT_EXTENSIONS.includes(resolveExtensionMatch[0])) {
+    const extensionParts = resolveExtensionMatch[0].split('.');
+
+    return {
+      ...file,
+      localPath: file.localPath.replace(resolveExtensionMatch[0], `.${extensionParts[extensionParts.length - 1]}`),
+    };
+  }
+
+  return file;
+};
diff --git a/src/pack.ts b/src/pack.ts
index 649eafc1..86d3fe77 100644
--- a/src/pack.ts
+++ b/src/pack.ts
@@ -9,7 +9,7 @@ import semver from 'semver';
 import type Serverless from 'serverless';
 
 import { ONLY_PREFIX, SERVERLESS_FOLDER } from './constants';
-import { assertIsString, doSharePath, flatDep, getDepsFromBundle, isESM } from './helper';
+import { assertIsString, doSharePath, flatDep, getDepsFromBundle, isESM, stripResolveExtensions } from './helper';
 import { getPackager } from './packagers';
 import { humanSize, trimExtension, zip } from './utils';
 
@@ -114,7 +114,16 @@ export async function pack(this: EsbuildServerlessPlugin) {
       onlyFiles: true,
     })
     .filter((file) => !excludedFiles.includes(file))
-    .map((localPath) => ({ localPath, rootPath: path.join(buildDirPath, localPath) }));
+    .map((localPath) => ({ localPath, rootPath: path.join(buildDirPath, localPath) }))
+    .map((file) => {
+      if (this.buildOptions?.resolveExtensions && this.buildOptions.resolveExtensions.length > 0) {
+        if (this.options.stripResolveExtensions) {
+          return stripResolveExtensions(file, this.buildOptions.resolveExtensions);
+        }
+      }
+
+      return file;
+    });
 
   if (isEmpty(files)) {
     this.log.verbose('Packaging: No files found. Skipping esbuild.');
diff --git a/src/tests/helper.test.ts b/src/tests/helper.test.ts
index d58fb6cf..54d960d4 100644
--- a/src/tests/helper.test.ts
+++ b/src/tests/helper.test.ts
@@ -2,9 +2,9 @@ import fs from 'fs-extra';
 import os from 'os';
 import path from 'path';
 
-import { extractFunctionEntries, flatDep, getDepsFromBundle, isESM } from '../helper';
+import { extractFunctionEntries, flatDep, getDepsFromBundle, isESM, stripResolveExtensions } from '../helper';
 
-import type { Configuration, DependencyMap } from '../types';
+import type { Configuration, DependencyMap, IFile } from '../types';
 
 jest.mock('fs-extra');
 
@@ -643,3 +643,15 @@ describe('flatDeps', () => {
     });
   });
 });
+
+describe('stripResolveExtensions', () => {
+  it('should remove custom extension prefixes', () => {
+    const result = stripResolveExtensions({ localPath: 'test.custom.js' } as IFile, ['.custom.js']);
+    expect(result.localPath).toEqual('test.js');
+  });
+
+  it('should ignore prefixes not inside the resolve extensions list', () => {
+    const result = stripResolveExtensions({ localPath: 'test.other.js' } as IFile, ['.custom.js']);
+    expect(result.localPath).toEqual('test.other.js');
+  });
+});
diff --git a/src/types.ts b/src/types.ts
index e6a16722..8990b122 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -9,6 +9,7 @@ export type ReturnPluginsFn = (sls: Serverless) => Plugins;
 
 export interface ImprovedServerlessOptions extends Serverless.Options {
   package?: string;
+  stripResolveExtensions?: boolean;
 }
 
 export interface WatchConfiguration {