fix(src): ensure deprecated config option is still supported by prettierFormatter

Addresses comment by @layershifter in #139

Author: Xunnamius

src/formatters/prettier.ts

@@ -40,26 +40,40 @@ export type { PrettierOptions };
  * @see https://prettier.io/docs/en/options.html#file-path
  */
 export const prettierFormatter: ResultFormatter<{
+  /**
+   * Options passed directly to prettier, allowing you to override the defaults.
+   */
   prettierOptions: MaybePrettierOptions;
+  /**
+   * If this deprecated parameter is given as an argument, treat it as the value
+   * of `prettierOptions`. Otherwise, it should not be used.
+   *
+   * @deprecated Use `prettierOptions` instead.
+   */
+  config: MaybePrettierOptions;
 }> = (
   code,
   {
     cwd = process.cwd(),
     filename,
     filepath = filename || path.join(cwd, 'dummy.js'),
-    prettierOptions = getCachedConfig(cwd)
+    config,
+    prettierOptions = config || getCachedConfig(cwd)
   } = {}
 ) => {
-  debug('cwd: %O', cwd);
-  debug('filepath: %O', filepath);
-  debug('original  code: %O', code);
-
-  const formattedCode = formatWithPrettier(code, {
+  const finalPrettierOptions = {
     filepath,
     ...prettierOptions
-  });
+  };
 
+  debug('cwd: %O', cwd);
+  debug('filepath: %O', filepath);
+  debug('prettier options: %O', finalPrettierOptions);
+  debug('original code: %O', code);
+
+  const formattedCode = formatWithPrettier(code, finalPrettierOptions);
   debug('formatted code: %O', code);
+
   return formattedCode;
 };
 

test/unit-formatters-prettier.test.ts

@@ -1,16 +1,55 @@
 import os from 'node:os';
+import path from 'node:path';
+
+import prettier from 'prettier';
+
 import { prettierFormatter } from '../src/formatters/prettier';
 
-test('uses default format with no available config', () => {
+import type { AnyFunction } from '@xunnamius/jest-types';
+
+type SpiedFunction<T extends AnyFunction> = jest.SpyInstance<
+  ReturnType<T>,
+  Parameters<T>
+>;
+
+let prettierSpy: SpiedFunction<typeof prettier.format>;
+
+beforeEach(() => {
+  prettierSpy = jest.spyOn(prettier, 'format');
+});
+
+it('uses default prettier options when no user-supplied config is available', () => {
   expect.hasAssertions();
 
   const result = prettierFormatter(`  var a = 'hi'  `, { cwd: os.tmpdir() });
   expect(result).toBe('var a = "hi";\n');
 });
 
-test('defaults all options', () => {
+it('uses user-supplied prettier config at project root if available (found starting at cwd)', () => {
   expect.hasAssertions();
 
   const result = prettierFormatter(`var a = "hi";`);
   expect(result).toBe(`var a = 'hi';\n`);
 });
+
+it('treats deprecated `filename` option as if it were `filepath`', () => {
+  expect.hasAssertions();
+
+  const expectedFilename = path.join(__dirname, 'fake.js');
+  prettierFormatter(`  var a = 'hi'  `, { filename: expectedFilename });
+
+  expect(prettierSpy.mock.calls).toMatchObject([
+    [expect.any(String), expect.objectContaining({ filepath: expectedFilename })]
+  ]);
+});
+
+it('treats deprecated `config` option as if it were `prettierOptions`', () => {
+  expect.hasAssertions();
+
+  const expectedConfig = { endOfLine: 'crlf' } as const;
+  prettierFormatter(`  var a = 'hi'  `, { config: expectedConfig });
+
+  expect(prettierSpy.mock.calls).toMatchObject([
+    [expect.any(String), expect.objectContaining(expectedConfig)]
+  ]);
+});