feat: support inline diff options and support printBasicPrototype

docs/config/index.md

@@ -2284,22 +2284,32 @@ export default defineConfig({
 ### diff
 
 - **Type:** `string`
-- **CLI:** `--diff=<value>`
+- **CLI:** `--diff=<path>`
 
-Path to a diff config that will be used to generate diff interface. Useful if you want to customize diff display.
+`DiffOptions` object or a path to a module which exports `DiffOptions`. Useful if you want to customize diff display.
+
+For example, as a config object:
 
 :::code-group
-```ts [vitest.diff.ts]
-import type { DiffOptions } from 'vitest'
-import c from 'tinyrainbow'
+```ts [vitest.config.js]
+import { defineConfig } from 'vitest/config'
+import c from 'picocolors'
 
-export default {
-  aIndicator: c.bold('--'),
-  bIndicator: c.bold('++'),
-  omitAnnotationLines: true,
-} satisfies DiffOptions
+export default defineConfig({
+  test: {
+    diff: {
+      aIndicator: c.bold('--'),
+      bIndicator: c.bold('++'),
+      omitAnnotationLines: true,
+    }
+  }
+})
 ```
+:::
 
+Or as a module:
+
+:::code-group
 ```ts [vitest.config.js]
 import { defineConfig } from 'vitest/config'
 
@@ -2309,12 +2319,32 @@ export default defineConfig({
   }
 })
 ```
+
+```ts [vitest.diff.ts]
+import type { DiffOptions } from 'vitest'
+import c from 'picocolors'
+
+export default {
+  aIndicator: c.bold('--'),
+  bIndicator: c.bold('++'),
+  omitAnnotationLines: true,
+} satisfies DiffOptions
+```
 :::
 
+#### diff.expand
+
+- **Type**: `boolean`
+- **Default**: `true`
+- **CLI:** `--diff.expand=false`
+
+Expand all common lines.
+
 #### diff.truncateThreshold
 
 - **Type**: `number`
 - **Default**: `0`
+- **CLI:** `--diff.truncateThreshold=<path>`
 
 The maximum length of diff result to be displayed. Diffs above this threshold will be truncated.
 Truncation won't take effect with default value 0.
@@ -2323,6 +2353,7 @@ Truncation won't take effect with default value 0.
 
 - **Type**: `string`
 - **Default**: `'... Diff result is truncated'`
+- **CLI:** `--diff.truncateAnnotation=<annotation>`
 
 Annotation that is output at the end of diff result if it's truncated.
 
@@ -2333,6 +2364,13 @@ 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`
+
+Print basic prototype `Object` and `Array` in diff output
+
 ### fakeTimers
 
 - **Type:** `FakeTimerInstallOpts`

packages/browser/src/node/plugin.ts

@@ -230,7 +230,7 @@ export default (browserServer: BrowserServer, base = '/'): Plugin[] => {
           'msw/browser',
         ]
 
-        if (project.config.diff) {
+        if (typeof project.config.diff === 'string') {
           entries.push(project.config.diff)
         }
 

packages/utils/src/diff/index.ts

@@ -23,7 +23,7 @@ import { getType } from './getType'
 import { normalizeDiffOptions } from './normalizeDiffOptions'
 import { diffStringsRaw, diffStringsUnified } from './printDiffs'
 
-export type { DiffOptions, DiffOptionsColor } from './types'
+export type { DiffOptions, DiffOptionsColor, SerializedDiffOptions } from './types'
 
 export { diffLinesRaw, diffLinesUnified, diffLinesUnified2 }
 export { diffStringsRaw, diffStringsUnified }
@@ -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

@@ -26,12 +26,29 @@ export interface DiffOptions {
   includeChangeCounts?: boolean
   omitAnnotationLines?: boolean
   patchColor?: DiffOptionsColor
+  printBasicPrototype?: boolean
   compareKeys?: CompareKeys
   truncateThreshold?: number
   truncateAnnotation?: string
   truncateAnnotationColor?: DiffOptionsColor
 }
 
+export interface SerializedDiffOptions {
+  aAnnotation?: string
+  aIndicator?: string
+  bAnnotation?: string
+  bIndicator?: string
+  commonIndicator?: string
+  contextLines?: number
+  emptyFirstOrLastLinePlaceholder?: string
+  expand?: boolean
+  includeChangeCounts?: boolean
+  omitAnnotationLines?: boolean
+  printBasicPrototype?: boolean
+  truncateThreshold?: number
+  truncateAnnotation?: string
+}
+
 export interface DiffOptionsNormalized {
   aAnnotation: string
   aColor: DiffOptionsColor
@@ -51,6 +68,7 @@ export interface DiffOptionsNormalized {
   includeChangeCounts: boolean
   omitAnnotationLines: boolean
   patchColor: DiffOptionsColor
+  printBasicPrototype: boolean
   truncateThreshold: number
   truncateAnnotation: string
   truncateAnnotationColor: DiffOptionsColor

packages/vitest/src/node/cli/cli-config.ts

@@ -599,9 +599,58 @@ export const cliOptionsConfig: VitestCLIOptions = {
   },
   diff: {
     description:
-      'Path to a diff config that will be used to generate diff interface',
+      'DiffOptions object or a path to a module which exports DiffOptions object',
     argument: '<path>',
-    normalize: true,
+    subcommands: {
+      aAnnotation: {
+        description: 'Annotation for expected lines (default: `Expected`)',
+        argument: '<annotation>',
+      },
+      aIndicator: {
+        description: 'Indicator for expected lines (default: `-`)',
+        argument: '<indicator>',
+      },
+      bAnnotation: {
+        description: 'Annotation for received lines (default: `Received`)',
+        argument: '<annotation>',
+      },
+      bIndicator: {
+        description: 'Indicator for received lines (default: `+`)',
+        argument: '<indicator>',
+      },
+      commonIndicator: {
+        description: 'Indicator for common lines (default: ` `)',
+        argument: '<indicator>',
+      },
+      contextLines: {
+        description: 'Number of lines of context to show around each change (default: `5`)',
+        argument: '<lines>',
+      },
+      emptyFirstOrLastLinePlaceholder: {
+        description: 'Placeholder for an empty first or last line (default: `""`)',
+        argument: '<placeholder>',
+      },
+      expand: {
+        description: 'Expand all common lines (default: `true`)',
+      },
+      includeChangeCounts: {
+        description: 'Include comparison counts in diff output (default: `false`)',
+      },
+      omitAnnotationLines: {
+        description: 'Omit annotation lines from the output (default: `false`)',
+      },
+      printBasicPrototype: {
+        description: 'Print basic prototype Object and Array (default: `true`)',
+      },
+      truncateThreshold: {
+        description: 'Number of lines to show before and after each change (default: `0`)',
+        argument: '<threshold>',
+      },
+      truncateAnnotation: {
+        description: 'Annotation for truncated lines (default: `... Diff result is truncated`)',
+        argument: '<annotation>',
+      },
+    },
   },
   exclude: {
     description: 'Additional file globs to be excluded from test',

packages/vitest/src/node/config/resolveConfig.ts

@@ -578,7 +578,7 @@ export function resolveConfig(
     }
   }
 
-  if (resolved.diff) {
+  if (typeof resolved.diff === 'string') {
     resolved.diff = resolvePath(resolved.diff, resolved.root)
     resolved.forceRerunTriggers.push(resolved.diff)
   }

packages/vitest/src/node/config/serializeConfig.ts

@@ -37,6 +37,7 @@ export function serializeConfig(
     pool: config.pool,
     expect: config.expect,
     snapshotSerializers: config.snapshotSerializers,
+    // TODO: non serializable function?
     diff: config.diff,
     retry: config.retry,
     disableConsoleIntercept: config.disableConsoleIntercept,

packages/vitest/src/node/types/config.ts

@@ -2,6 +2,7 @@ import type { FakeTimerInstallOpts } from '@sinonjs/fake-timers'
 import type { PrettyFormatOptions } from '@vitest/pretty-format'
 import type { SequenceHooks, SequenceSetupFiles } from '@vitest/runner'
 import type { SnapshotStateOptions } from '@vitest/snapshot'
+import type { SerializedDiffOptions } from '@vitest/utils/diff'
 import type { AliasOptions, ConfigEnv, DepOptimizationConfig, ServerOptions, UserConfig as ViteUserConfig } from 'vite'
 import type { ViteNodeServerOptions } from 'vite-node'
 import type { ChaiConfig } from '../../integrations/chai/config'
@@ -563,7 +564,7 @@ export interface InlineConfig {
   /**
    * Path to a module which has a default export of diff config.
    */
-  diff?: string
+  diff?: string | SerializedDiffOptions
 
   /**
    * Paths to snapshot serializer modules.
@@ -979,7 +980,7 @@ export interface ResolvedConfig
   mode: VitestRunMode
 
   base?: string
-  diff?: string
+  diff?: string | SerializedDiffOptions
   bail?: number
 
   setupFiles: string[]

packages/vitest/src/runtime/config.ts

@@ -3,6 +3,7 @@ import type { PrettyFormatOptions } from '@vitest/pretty-format'
 import type { SequenceHooks, SequenceSetupFiles } from '@vitest/runner'
 import type { SnapshotUpdateState } from '@vitest/snapshot'
 import type { SnapshotEnvironment } from '@vitest/snapshot/environment'
+import type { SerializedDiffOptions } from '@vitest/utils/diff'
 
 /**
  * Config that tests have access to.
@@ -98,7 +99,7 @@ export interface SerializedConfig {
     showDiff?: boolean
     truncateThreshold?: number
   } | undefined
-  diff: string | undefined
+  diff: string | SerializedDiffOptions | undefined
   retry: number
   includeTaskLocation: boolean | undefined
   inspect: boolean | string | undefined

packages/vitest/src/runtime/setup-common.ts

@@ -47,6 +47,9 @@ export async function loadDiffConfig(
   config: SerializedConfig,
   executor: VitestExecutor,
 ) {
+  if (typeof config.diff === 'object') {
+    return config.diff
+  }
   if (typeof config.diff !== 'string') {
     return
   }

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

@@ -0,0 +1,20 @@
+import { expect, test } from 'vitest'
+
+test('large diff', () => {
+  const x = [...Array(30)].map((_, i) => i);
+  const y = [...x];
+  y[0] = 1000;
+  y[15] = 2000;
+  y[29] = 3000;
+  expect(x).toEqual(y)
+})
+
+test("printBasicPrototype", () => {
+  expect({
+    obj: { k: "foo" },
+    arr: [1, 2]
+  }).toEqual({
+    obj: { k: "bar" },
+    arr: [1, 3]
+  });
+})

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

@@ -0,0 +1,10 @@
+import {defineConfig} from 'vitest/config'
+
+export default defineConfig({
+  test: {
+    diff: {
+      // expand: false,
+      // printBasicPrototype: false,
+    }
+  }
+})