feat: add noPrefix options (#21)

Author: yeonjuan

README.md

@@ -52,6 +52,20 @@ console.log(result);
 // }
 ```
 
+### Options
+
+#### `noPrefix` (boolean)
+
+Specifies whether the git diff command is used with the `--no-prefix` option. (default: `false`)
+
+```ts
+// git diff HEAD~3 --no-prefix
+
+const result = parseGitDiff(DIFF, {
+  noPrefix: true,
+});
+```
+
 ## Examples
 
 <details>

src/__tests__/options.test.ts

@@ -0,0 +1,39 @@
+import parseGitDiff from '../parse-git-diff';
+import { ChangedFile, RenamedFile } from '../types';
+
+const getDiffFixture = ({
+  srcPrefix = 'a/',
+  dstPrefix = 'b/',
+}) => `diff --git ${srcPrefix}b/bbb.md ${dstPrefix}b/bbb.md
+index 0e05564..aa39060 100644
+--- ${srcPrefix}b/bbb.md
++++ ${dstPrefix}b/bbb.md
+@@ -1,2 +1 @@
+ newfile
+-newline
++newline
+\ No newline at end of file`;
+
+describe('options', () => {
+  it('noPrefix=true', () => {
+    const output = parseGitDiff(
+      getDiffFixture({ srcPrefix: '', dstPrefix: '' }),
+      {
+        noPrefix: true,
+      }
+    );
+
+    expect((output.files[0] as ChangedFile).path).toBe('b/bbb.md');
+  });
+
+  it('noPrefix=false', () => {
+    const output = parseGitDiff(
+      getDiffFixture({ srcPrefix: 'a/', dstPrefix: 'b/' }),
+      {
+        noPrefix: false,
+      }
+    );
+
+    expect((output.files[0] as ChangedFile).path).toBe('b/bbb.md');
+  });
+});

src/context.ts

@@ -1,8 +1,15 @@
+import { FilledGitDiffOptions, GitDiffOptions } from './types';
+
 export default class Context {
   private line: number = 1;
   private lines: string[] = [];
-  public constructor(diff: string) {
+  public options: FilledGitDiffOptions = {
+    noPrefix: false,
+  };
+  public constructor(diff: string, options?: GitDiffOptions) {
     this.lines = diff.split('\n');
+
+    this.options.noPrefix = !!options?.noPrefix;
   }
 
   public getCurLine(): string {

src/index.ts

@@ -17,4 +17,5 @@ export type {
   RenamedFile,
   AnyFileChange,
   GitDiff,
+  GitDiffOptions,
 } from './types.js';

src/parse-git-diff.ts

@@ -7,6 +7,8 @@ import type {
   ChunkRange,
   CombinedChunk,
   AnyChunk,
+  FilledGitDiffOptions,
+  GitDiffOptions,
 } from './types.js';
 import {
   ExtendedHeader,
@@ -15,8 +17,11 @@ import {
   LineType,
 } from './constants.js';
 
-export default function parseGitDiff(diff: string): GitDiff {
-  const ctx = new Context(diff);
+export default function parseGitDiff(
+  diff: string,
+  options?: GitDiffOptions
+): GitDiff {
+  const ctx = new Context(diff, options);
   const files = parseFileChanges(ctx);
 
   return {
@@ -229,8 +234,8 @@ function parseChunkHeader(ctx: Context) {
         ctx.nextLine();
         return {
           type: 'BinaryFiles',
-          fileA: fileA.replace('a/', ''),
-          fileB: fileB.replace('b/', ''),
+          fileA: getFilePath(ctx, fileA, 'src'),
+          fileB: getFilePath(ctx, fileB, 'dst'),
         } as const;
       }
 
@@ -280,8 +285,15 @@ function parseChangeMarkers(context: Context): {
   deleted: string;
   added: string;
 } | null {
-  const deleted = parseMarker(context, '--- ')?.replace('a/', '');
-  const added = parseMarker(context, '+++ ')?.replace('b/', '');
+  const deleterMarker = parseMarker(context, '--- ');
+  const deleted = deleterMarker
+    ? getFilePath(context, deleterMarker, 'src')
+    : deleterMarker;
+
+  const addedMarker = parseMarker(context, '+++ ');
+  const added = addedMarker
+    ? getFilePath(context, addedMarker, 'dst')
+    : addedMarker;
   return added && deleted ? { added, deleted } : null;
 }
 
@@ -364,3 +376,11 @@ function parseChanges(
 function getLineType(line: string): LineType | null {
   return CHAR_TYPE_MAP[line[0]] || null;
 }
+
+function getFilePath(ctx: Context, input: string, type: 'src' | 'dst') {
+  if (ctx.options.noPrefix) {
+    return input;
+  }
+  if (type === 'src') return input.replace(/^a\//, '');
+  if (type === 'dst') return input.replace(/^b\//, '');
+}

src/types.ts

@@ -84,3 +84,9 @@ export type AnyFileChange = ChangedFile | AddedFile | DeletedFile | RenamedFile;
 export interface GitDiff extends Base<'GitDiff'> {
   files: AnyFileChange[];
 }
+
+export interface FilledGitDiffOptions {
+  noPrefix: boolean;
+}
+
+export type GitDiffOptions = Partial<FilledGitDiffOptions>;