Add new utils for Web IDE store

- getDiffInfo determines if any diff exists in staged and unstaged
changes for this path
- isFileDeletedAndReadded does what the name suggests - tells
if a file is deleted in staged and readded in unstaged

app/assets/javascripts/ide/stores/getters.js

@@ -115,5 +115,30 @@ export const isOnDefaultBranch = (_state, getters) =>
 export const canPushToBranch = (_state, getters) =>
   getters.currentBranch && getters.currentBranch.can_push;
 
+export const isFileDeletedAndReadded = (state, getters) => path => {
+  const stagedFile = getters.getStagedFile(path);
+  const file = state.entries[path];
+  return Boolean(stagedFile && stagedFile.deleted && file.tempFile);
+};
+
+// checks if any diff exists in the staged or unstaged changes for this path
+export const getDiffInfo = (state, getters) => path => {
+  const stagedFile = getters.getStagedFile(path);
+  const file = state.entries[path];
+  const renamed = file.prevPath ? file.path !== file.prevPath : false;
+  const deletedAndReadded = getters.isFileDeletedAndReadded(path);
+  const deleted = deletedAndReadded ? false : file.deleted;
+  const tempFile = deletedAndReadded ? false : file.tempFile;
+  const changed = file.content !== (deletedAndReadded ? stagedFile.raw : file.raw);
+
+  return {
+    exists: changed || renamed || deleted || tempFile,
+    changed,
+    renamed,
+    deleted,
+    tempFile,
+  };
+};
+
 // prevent babel-plugin-rewire from generating an invalid default during karma tests
 export default () => {};

changelogs/unreleased/39498-part-1.yml

+---
+title: "!21542 Part 1: Add new utils for Web IDE store"
+merge_request: 21673
+author:
+type: fixed

spec/frontend/ide/stores/getters_spec.js

 import * as getters from '~/ide/stores/getters';
-import state from '~/ide/stores/state';
+import { createStore } from '~/ide/stores';
 import { file } from '../helpers';
 
 describe('IDE store getters', () => {
   let localState;
+  let localStore;
 
   beforeEach(() => {
-    localState = state();
+    localStore = createStore();
+    localState = localStore.state;
   });
 
   describe('activeFile', () => {
@@ -310,4 +312,90 @@ describe('IDE store getters', () => {
       expect(getters.canPushToBranch({}, localGetters)).toBeFalsy();
     });
   });
+
+  describe('isFileDeletedAndReadded', () => {
+    const f = { ...file('sample'), content: 'sample', raw: 'sample' };
+
+    it.each([
+      {
+        entry: { ...f, tempFile: true },
+        staged: { ...f, deleted: true },
+        output: true,
+      },
+      {
+        entry: { ...f, content: 'changed' },
+        staged: { ...f, content: 'changed' },
+        output: false,
+      },
+      {
+        entry: { ...f, content: 'changed' },
+        output: false,
+      },
+    ])(
+      'checks staged and unstaged files to see if a file was deleted and readded (case %#)',
+      ({ entry, staged, output }) => {
+        Object.assign(localState, {
+          entries: {
+            [entry.path]: entry,
+          },
+          stagedFiles: [],
+        });
+
+        if (staged) localState.stagedFiles.push(staged);
+
+        expect(localStore.getters.isFileDeletedAndReadded(entry.path)).toBe(output);
+      },
+    );
+  });
+
+  describe('getDiffInfo', () => {
+    const f = { ...file('sample'), content: 'sample', raw: 'sample' };
+    it.each([
+      {
+        entry: { ...f, tempFile: true },
+        staged: { ...f, deleted: true },
+        output: { deleted: false, changed: false, tempFile: false },
+      },
+      {
+        entry: { ...f, tempFile: true, content: 'changed', raw: '' },
+        staged: { ...f, deleted: true },
+        output: { deleted: false, changed: true, tempFile: false },
+      },
+      {
+        entry: { ...f, content: 'changed' },
+        output: { changed: true },
+      },
+      {
+        entry: { ...f, content: 'sample' },
+        staged: { ...f, content: 'changed' },
+        output: { changed: false },
+      },
+      {
+        entry: { ...f, deleted: true },
+        output: { deleted: true, changed: false },
+      },
+      {
+        entry: { ...f, prevPath: 'old_path' },
+        output: { renamed: true, changed: false },
+      },
+      {
+        entry: { ...f, prevPath: 'old_path', content: 'changed' },
+        output: { renamed: true, changed: true },
+      },
+    ])(
+      'compares changes in a file entry and returns a resulting diff info (case %#)',
+      ({ entry, staged, output }) => {
+        Object.assign(localState, {
+          entries: {
+            [entry.path]: entry,
+          },
+          stagedFiles: [],
+        });
+
+        if (staged) localState.stagedFiles.push(staged);
+
+        expect(localStore.getters.getDiffInfo(entry.path)).toEqual(expect.objectContaining(output));
+      },
+    );
+  });
 });