feat(utils): support diff.printBasicPrototype, Adding possibility to get rid of prototypes from the output

docs/config/index.md

@@ -2297,6 +2297,7 @@ export default {
   aIndicator: c.bold('--'),
   bIndicator: c.bold('++'),
   omitAnnotationLines: true,
+  printBasicPrototype: false,
 } satisfies DiffOptions
 ```
 
@@ -2333,6 +2334,13 @@ Annotation that is output at the end of diff result if it's truncated.
 
 Color of truncate annotation, default is output with no color.
 
+#### diff.printBasicPrototype
+
+- **Type**: `boolean`
+- **Default**: `true`
+
+Allows to set pretty-format option printBasicPrototype for diff output
+
 ### fakeTimers
 
 - **Type:** `FakeTimerInstallOpts`

packages/utils/src/diff/index.ts

@@ -180,11 +180,12 @@ function getFormatOptions(
   formatOptions: PrettyFormatOptions,
   options?: DiffOptions,
 ): PrettyFormatOptions {
-  const { compareKeys } = normalizeDiffOptions(options)
+  const { compareKeys, printBasicPrototype } = normalizeDiffOptions(options)
 
   return {
     ...formatOptions,
     compareKeys,
+    printBasicPrototype,
   }
 }
 

packages/utils/src/diff/normalizeDiffOptions.ts

@@ -34,6 +34,7 @@ function getDefaultOptions(): DiffOptionsNormalized {
     includeChangeCounts: false,
     omitAnnotationLines: false,
     patchColor: c.yellow,
+    printBasicPrototype: true,
     truncateThreshold: DIFF_TRUNCATE_THRESHOLD_DEFAULT,
     truncateAnnotation: '... Diff result is truncated',
     truncateAnnotationColor: noColor,

packages/utils/src/diff/types.ts

@@ -26,6 +26,7 @@ export interface DiffOptions {
   includeChangeCounts?: boolean
   omitAnnotationLines?: boolean
   patchColor?: DiffOptionsColor
+  printBasicPrototype?: boolean
   compareKeys?: CompareKeys
   truncateThreshold?: number
   truncateAnnotation?: string
@@ -51,6 +52,7 @@ export interface DiffOptionsNormalized {
   includeChangeCounts: boolean
   omitAnnotationLines: boolean
   patchColor: DiffOptionsColor
+  printBasicPrototype: boolean
   truncateThreshold: number
   truncateAnnotation: string
   truncateAnnotationColor: DiffOptionsColor

test/config/fixtures/diff/basic.test.ts

@@ -0,0 +1,11 @@
+import { expect, test } from 'vitest'
+
+test("printBasicPrototype false", () => {
+  expect({
+    obj: { k: "foo" },
+    arr: [1, 2]
+  }).toEqual({
+    obj: { k: "bar" },
+    arr: [1, 3]
+  });
+})

test/config/fixtures/diff/diff.ts

@@ -0,0 +1,5 @@
+import { DiffOptions } from "vitest";
+
+export default {
+  printBasicPrototype: false
+} satisfies DiffOptions

test/config/fixtures/diff/vite.config.ts

@@ -0,0 +1,7 @@
+import {defineConfig} from 'vitest/config'
+
+export default defineConfig({
+  test: {
+    diff: './diff.ts'
+  }
+})

test/config/test/__snapshots__/diff.test.ts.snap

@@ -0,0 +1,20 @@
+// Vitest Snapshot v1, https://vitest.dev/guide/snapshot.html
+
+exports[`diff 1`] = `
+[
+  "- Expected
++ Received
+
+  {
+    "arr": [
+      1,
+-     3,
++     2,
+    ],
+    "obj": {
+-     "k": "bar",
++     "k": "foo",
+    },
+  }",
+]
+`;

test/config/test/diff.test.ts

@@ -0,0 +1,15 @@
+import { stripVTControlCharacters } from 'node:util'
+import { expect, test } from 'vitest'
+import { runVitest } from '../../test-utils'
+
+test('diff', async () => {
+  const { ctx } = await runVitest({
+    root: './fixtures/diff',
+  })
+  const errors = ctx!.state.getFiles().flatMap(f =>
+    f.tasks.flatMap(t => t.result?.errors ?? []),
+  )
+  expect(
+    errors.map(e => e.diff && stripVTControlCharacters(e.diff)),
+  ).matchSnapshot()
+})

test/config/test/failures.test.ts

@@ -247,7 +247,9 @@ test('coverage.autoUpdate cannot update thresholds when configuration file doesn
 })
 
 test('boolean flag 100 should not crash CLI', async () => {
-  const { stderr } = await runVitestCli('--coverage.enabled', '--coverage.thresholds.100')
+  let { stderr } = await runVitestCli('--coverage.enabled', '--coverage.thresholds.100')
+  // non-zero coverage shows up, which is non-deterministic, so strip it.
+  stderr = stderr.replace(/\([0-9.]+%\) does/g, '(0%) does')
 
   expect(stderr).toMatch('ERROR: Coverage for lines (0%) does not meet global threshold (100%)')
   expect(stderr).toMatch('ERROR: Coverage for functions (0%) does not meet global threshold (100%)')