feat: add context to Chunk

src/__fixtures__/chunk-context

@@ -0,0 +1,7 @@
+diff --git a/rename.js b/rename.js
+index aa39060..0e05564 100644
+--- a/rename.js
++++ b/rename.js
+@@ -4 +4,5 @@ function hello() {
+   // hello world
++  console.log("hello world");

src/__tests__/__snapshots__/all.test.ts.snap

@@ -19,6 +19,7 @@ exports[`aa parse \`all\` 1`] = `
               "type": "DeletedLine",
             },
           ],
+          "context": undefined,
           "fromFileRange": {
             "lines": 2,
             "start": 1,
@@ -43,6 +44,7 @@ exports[`aa parse \`all\` 1`] = `
               "type": "DeletedLine",
             },
           ],
+          "context": undefined,
           "fromFileRange": {
             "lines": 1,
             "start": 1,
@@ -67,6 +69,7 @@ exports[`aa parse \`all\` 1`] = `
               "type": "AddedLine",
             },
           ],
+          "context": undefined,
           "fromFileRange": {
             "lines": 0,
             "start": 0,
@@ -97,6 +100,7 @@ exports[`aa parse \`all\` 1`] = `
               "type": "AddedLine",
             },
           ],
+          "context": undefined,
           "fromFileRange": {
             "lines": 1,
             "start": 1,

src/__tests__/__snapshots__/chunk-context.test.ts.snap

@@ -0,0 +1,40 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`chunk-context parse \`chunk-context\` 1`] = `
+{
+  "files": [
+    {
+      "chunks": [
+        {
+          "changes": [
+            {
+              "content": "  // hello world",
+              "lineAfter": 4,
+              "lineBefore": 4,
+              "type": "UnchangedLine",
+            },
+            {
+              "content": "  console.log(\"hello world\");",
+              "lineAfter": 5,
+              "type": "AddedLine",
+            },
+          ],
+          "context": "function hello() {",
+          "fromFileRange": {
+            "lines": 4,
+            "start": 4,
+          },
+          "toFileRange": {
+            "lines": 5,
+            "start": 4,
+          },
+          "type": "Chunk",
+        },
+      ],
+      "path": "rename.js",
+      "type": "ChangedFile",
+    },
+  ],
+  "type": "GitDiff",
+}
+`;

src/__tests__/__snapshots__/conflict-file.test.ts.snap

@@ -76,6 +76,7 @@ exports[`conflict-file parse \`conflict-file\` 1`] = `
               "type": "UnchangedLine",
             },
           ],
+          "context": undefined,
           "fromFileRangeA": {
             "lines": 7,
             "start": 8,

src/__tests__/__snapshots__/deleted-file.test.ts.snap

@@ -13,6 +13,7 @@ exports[`deleted-file parse \`deleted-file\` 1`] = `
               "type": "DeletedLine",
             },
           ],
+          "context": undefined,
           "fromFileRange": {
             "lines": 1,
             "start": 1,

src/__tests__/__snapshots__/deleted-line.test.ts.snap

@@ -19,6 +19,7 @@ exports[`deleted-line parse \`deleted-line\` 1`] = `
               "type": "DeletedLine",
             },
           ],
+          "context": undefined,
           "fromFileRange": {
             "lines": 2,
             "start": 1,

src/__tests__/__snapshots__/message-line.test.ts.snap

@@ -28,6 +28,7 @@ exports[`message-line parse \`message-line\` 1`] = `
               "type": "MessageLine",
             },
           ],
+          "context": undefined,
           "fromFileRange": {
             "lines": 2,
             "start": 1,
@@ -67,6 +68,7 @@ exports[`message-line parse \`message-line\` 1`] = `
               "type": "MessageLine",
             },
           ],
+          "context": undefined,
           "fromFileRange": {
             "lines": 2,
             "start": 1,

src/__tests__/__snapshots__/new-file.test.ts.snap

@@ -13,6 +13,7 @@ exports[`new-file parse \`new-file\` 1`] = `
               "type": "AddedLine",
             },
           ],
+          "context": undefined,
           "fromFileRange": {
             "lines": 0,
             "start": 0,

src/__tests__/__snapshots__/new-line.test.ts.snap

@@ -19,6 +19,7 @@ exports[`new-line parse \`new-line\` 1`] = `
               "type": "AddedLine",
             },
           ],
+          "context": undefined,
           "fromFileRange": {
             "lines": 1,
             "start": 1,

src/__tests__/chunk-context.test.ts

@@ -0,0 +1,10 @@
+import { getFixture } from './test-utils';
+import parseGitDiff from '../parse-git-diff';
+
+describe('chunk-context', () => {
+  const fixture = getFixture('chunk-context');
+
+  it('parse `chunk-context`', () => {
+    expect(parseGitDiff(fixture)).toMatchSnapshot();
+  });
+});

src/parse-git-diff.ts

@@ -175,12 +175,13 @@ function parseExtendedHeader(ctx: Context) {
 
 function parseChunkHeader(ctx: Context) {
   const line = ctx.getCurLine();
-  const normalChunkExec = /^@@\s\-(\d+),?(\d+)?\s\+(\d+),?(\d+)?\s@@/.exec(
-    line
-  );
+  const normalChunkExec =
+    /^@@\s\-(\d+),?(\d+)?\s\+(\d+),?(\d+)?\s@@\s?(.+)?/.exec(line);
   if (!normalChunkExec) {
     const combinedChunkExec =
-      /^@@@\s\-(\d+),?(\d+)?\s\-(\d+),?(\d+)?\s\+(\d+),?(\d+)?\s@@@/.exec(line);
+      /^@@@\s\-(\d+),?(\d+)?\s\-(\d+),?(\d+)?\s\+(\d+),?(\d+)?\s@@@\s?(.+)?/.exec(
+        line
+      );
 
     if (!combinedChunkExec) {
       return null;
@@ -194,18 +195,22 @@ function parseChunkHeader(ctx: Context) {
       delLinesB,
       addStart,
       addLines,
+      context,
     ] = combinedChunkExec;
     ctx.nextLine();
     return {
+      context,
       type: 'Combined',
       fromFileRangeA: getRange(delStartA, delLinesA),
       fromFileRangeB: getRange(delStartB, delLinesB),
       toFileRange: getRange(addStart, addLines),
     } as const;
   }
-  const [all, delStart, delLines, addStart, addLines] = normalChunkExec;
+  const [all, delStart, delLines, addStart, addLines, context] =
+    normalChunkExec;
   ctx.nextLine();
   return {
+    context,
     type: 'Normal',
     toFileRange: getRange(addStart, addLines),
     fromFileRange: getRange(delStart, delLines),

src/types.ts

@@ -40,13 +40,15 @@ export interface Chunk extends Base<'Chunk'> {
   fromFileRange: ChunkRange;
   toFileRange: ChunkRange;
   changes: AnyLineChange[];
+  context: string | undefined;
 }
 
 export interface CombinedChunk extends Base<'CombinedChunk'> {
   fromFileRangeA: ChunkRange;
   fromFileRangeB: ChunkRange;
   toFileRange: ChunkRange;
   changes: AnyLineChange[];
+  context: string | undefined;
 }
 
 export type AnyChunk = Chunk | CombinedChunk;