refactor!: replace loupe.inspect with pretty-format (#9609)

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Co-authored-by: Codex <noreply@openai.com>

Author: 3 people

docs/api/test.md

@@ -618,7 +618,7 @@ test.each`
 ```
 
 ::: tip
-Vitest processes `$values` with Chai `format` method. If the value is too truncated, you can increase [chaiConfig.truncateThreshold](/config/chaiconfig#chaiconfig-truncatethreshold) in your config file.
+Vitest formats interpolated title values with its display formatter. If the value is too truncated, you can increase [taskTitleValueFormatTruncate](/config/tasktitlevalueformattruncate) in your config file.
 :::
 
 ## test.for

docs/config/chaiconfig.md

@@ -29,6 +29,4 @@ Influences whether or not the `showDiff` flag should be included in the thrown A
 - **Type:** `number`
 - **Default:** `40`
 
-Sets length threshold for actual and expected values in assertion errors. If this threshold is exceeded, for example for large data structures, the value is replaced with something like `[ Array(3) ]` or `{ Object (prop1, prop2) }`. Set it to `0` if you want to disable truncating altogether.
-
-This config option affects truncating values in `test.each` titles and inside the assertion error message.
+Sets length threshold for actual and expected values in assertion error messages. If this threshold is exceeded, for example for large data structures, the value is replaced with something like `[ Array(3) ]` or `{ Object (prop1, prop2) }`. Set it to `0` if you want to disable truncating altogether.

docs/config/tasktitlevalueformattruncate.md

@@ -0,0 +1,15 @@
+---
+title: taskTitleValueFormatTruncate | Config
+outline: deep
+---
+
+# taskTitleValueFormatTruncate <CRoot /> {#tasktitlevalueformattruncate}
+
+- **Type** `number`
+- **Default:** `40`
+
+Sets the length limit for formatted values interpolated into generated task titles.
+
+This affects values inserted by APIs like `test.each` and `test.for`, including both `$value` and `%` placeholder formatting.
+
+Set it to `0` to disable truncation.

packages/browser/src/client/tester/logger.ts

@@ -1,4 +1,4 @@
-import { browserFormat } from 'vitest/internal/browser'
+import { format } from 'vitest/internal/browser'
 import { getConfig } from '../utils'
 import { rpc } from './rpc'
 import { getBrowserRunner } from './runner'
@@ -30,7 +30,7 @@ export function setupConsoleLogSpy(): void {
 
   console.dir = (item, options) => {
     dir(item, options)
-    sendLog('stdout', browserFormat(item))
+    sendLog('stdout', processLog([item]))
   }
 
   console.dirxml = (...args) => {
@@ -114,7 +114,7 @@ function stderr(base: (...args: unknown[]) => void) {
 }
 
 function processLog(args: unknown[]) {
-  return browserFormat(...args)
+  return format(args, { multiline: true })
 }
 
 function sendLog(

packages/expect/src/jest-expect.ts

@@ -4,6 +4,7 @@ import type { Constructable } from '@vitest/utils'
 import type { AsymmetricMatcher } from './jest-asymmetric-matchers'
 import type { Assertion, ChaiPlugin } from './types'
 import { isMockFunction } from '@vitest/spy'
+import { inspect } from '@vitest/utils/display'
 import { assertTypes, ordinal } from '@vitest/utils/helpers'
 import c from 'tinyrainbow'
 import { JEST_MATCHERS_OBJECT } from './constants'
@@ -483,7 +484,7 @@ export const JestChaiExpect: ChaiPlugin = (chai, utils) => {
           && (args.length === 1 || jestEquals(expected, value, customTesters))
 
       const valueString
-        = args.length === 1 ? '' : ` with value ${utils.objDisplay(expected)}`
+        = args.length === 1 ? '' : ` with value ${inspect(expected, { truncate: 40 })}`
 
       return this.assert(
         pass,

packages/pretty-format/USAGE.md

@@ -51,11 +51,16 @@ Object {
 | `printBasicPrototype` | `boolean`        | `true`      | Print `Object` and `Array` prefixes for plain objects and arrays     |
 | `printFunctionName`   | `boolean`        | `true`      | Include or omit the function name                                    |
 | `printShadowRoot`     | `boolean`        | `true`      | Include shadow-root contents when formatting DOM nodes               |
+| `quoteKeys`           | `boolean`        | `true`      | Always quote object property keys                                    |
+| `singleQuote`         | `boolean`        | `false`     | Print strings using single quotes instead of double quotes           |
+| `spacingInner`        | `string`         | `\n`        | Whitespace after commas between items or entries                     |
+| `spacingOuter`        | `string`         | `\n`        | Whitespace just inside `[]` / `{}` delimiters                        |
 
 Important:
 
 - `plugins: []` means the package does not auto-enable its built-in plugins by default
 - Vitest features opt into their own plugin stacks and option presets
+- `min: true` also changes the defaults of other options to `spacingInner: ' '`, `spacingOuter: ''`, and `printBasicPrototype: false`
 
 ## Built-in Plugins
 

packages/pretty-format/src/collections.ts

@@ -21,7 +21,7 @@ function getKeysOfEnumerableProperties(object: Record<string, unknown>, compareK
     }
   }
 
-  return keys as Array<string>
+  return keys
 }
 
 /**
@@ -37,6 +37,7 @@ export function printIteratorEntries(
   refs: Refs,
   printer: Printer,
   separator = ': ',
+  length?: number,
 ): string {
   let result = ''
   let width = 0
@@ -51,7 +52,7 @@ export function printIteratorEntries(
       result += indentationNext
 
       if (width++ === config.maxWidth) {
-        result += '…'
+        result += typeof length === 'number' ? `…(${length - width + 1})` : '…'
         break
       }
 
@@ -100,6 +101,7 @@ export function printIteratorValues(
   depth: number,
   refs: Refs,
   printer: Printer,
+  length?: number,
 ): string {
   let result = ''
   let width = 0
@@ -114,7 +116,7 @@ export function printIteratorValues(
       result += indentationNext
 
       if (width++ === config.maxWidth) {
-        result += '…'
+        result += typeof length === 'number' ? `…(${length - width + 1})` : '…'
         break
       }
 
@@ -163,7 +165,7 @@ export function printListItems(
       result += indentationNext
 
       if (i === config.maxWidth) {
-        result += '…'
+        result += `…(${length - i})`
         break
       }
 
@@ -197,27 +199,37 @@ export function printListItems(
  * without surrounding punctuation (for example, braces)
  */
 export function printObjectProperties(
-  val: Record<string, unknown>,
+  val: Record<string | symbol, unknown>,
   config: Config,
   indentation: string,
   depth: number,
   refs: Refs,
   printer: Printer,
+  compareKeysOverride: CompareKeys = config.compareKeys,
 ): string {
   let result = ''
-  const keys = getKeysOfEnumerableProperties(val, config.compareKeys)
+  const keys = getKeysOfEnumerableProperties(val, compareKeysOverride)
 
   if (keys.length > 0) {
     result += config.spacingOuter
 
     const indentationNext = indentation + config.indent
 
     for (let i = 0; i < keys.length; i++) {
+      result += indentationNext
+
+      if (i === config.maxWidth) {
+        result += `…(${keys.length - i})`
+        break
+      }
+
       const key = keys[i]
-      const name = printer(key, config, indentationNext, depth, refs)
+      const name = !config.quoteKeys && isUnquotableKey(key)
+        ? key as string
+        : printer(key, config, indentationNext, depth, refs)
       const value = printer(val[key], config, indentationNext, depth, refs)
 
-      result += `${indentationNext + name}: ${value}`
+      result += `${name}: ${value}`
 
       if (i < keys.length - 1) {
         result += `,${config.spacingInner}`
@@ -232,3 +244,11 @@ export function printObjectProperties(
 
   return result
 }
+
+// https://github.com/nodejs/node/blob/61102cdbb3d59155ad5bb4fc9419627a31e63f7a/lib/internal/util/inspect.js#L249
+// /^[a-zA-Z_][a-zA-Z_0-9]*$/
+const keyStrRegExp = /^[a-z_]\w*$/i
+
+function isUnquotableKey(key: string | symbol): boolean {
+  return typeof key === 'string' && key !== '__proto__' && keyStrRegExp.test(key)
+}

packages/pretty-format/src/index.ts

@@ -111,6 +111,7 @@ function printBasicValue(
   printFunctionName: boolean,
   escapeRegex: boolean,
   escapeString: boolean,
+  singleQuote: boolean,
 ): string | null {
   if (val === true || val === false) {
     return `${val}`
@@ -131,10 +132,15 @@ function printBasicValue(
     return printBigInt(val)
   }
   if (typeOf === 'string') {
+    const q = singleQuote ? '\'' : '"'
     if (escapeString) {
-      return `"${val.replaceAll(/"|\\/g, '\\$&')}"`
+      // escape quote in each case, e.g.
+      //   it's me -> 'it\'s me'
+      //   say "hi" -> "say \"hi\""
+      const escapePattern = singleQuote ? /['\\]/g : /["\\]/g
+      return `${q}${val.replaceAll(escapePattern, '\\$&')}${q}`
     }
-    return `"${val}"`
+    return `${q}${val}${q}`
   }
   if (typeOf === 'function') {
     return printFunction(val, printFunctionName)
@@ -229,11 +235,9 @@ function printComplexValue(
     return hitMaxDepth
       ? `[${val.constructor.name}]`
       : `${
-        min
+        !config.printBasicPrototype && val.constructor.name === 'Array'
           ? ''
-          : !config.printBasicPrototype && val.constructor.name === 'Array'
-              ? ''
-              : `${val.constructor.name} `
+          : `${val.constructor.name} `
       }[${printListItems(val, config, indentation, depth, refs, printer)}]`
   }
   if (toStringed === '[object Map]') {
@@ -247,6 +251,7 @@ function printComplexValue(
         refs,
         printer,
         ' => ',
+        val.size,
       )}}`
   }
   if (toStringed === '[object Set]') {
@@ -259,6 +264,7 @@ function printComplexValue(
         depth,
         refs,
         printer,
+        val.size,
       )}}`
   }
 
@@ -267,11 +273,9 @@ function printComplexValue(
   return hitMaxDepth || isWindow(val)
     ? `[${getConstructorName(val)}]`
     : `${
-      min
+      !config.printBasicPrototype && getConstructorName(val) === 'Object'
         ? ''
-        : !config.printBasicPrototype && getConstructorName(val) === 'Object'
-            ? ''
-            : `${getConstructorName(val)} `
+        : `${getConstructorName(val)} `
     }{${printObjectProperties(
       val,
       config,
@@ -300,13 +304,14 @@ const ErrorPlugin: NewPlugin = {
     const name = val.name !== 'Error' ? val.name : getConstructorName(val as any)
     return hitMaxDepth
       ? `[${name}]`
-      : `${name} {${printIteratorEntries(
-        Object.entries(entries).values(),
+      : `${name} {${printObjectProperties(
+        entries,
         config,
         indentation,
         depth,
         refs,
         printer,
+        null,
       )}}`
   },
 }
@@ -392,6 +397,7 @@ function printer(
       config.printFunctionName,
       config.escapeRegex,
       config.escapeString,
+      config.singleQuote,
     )
     if (basicResult !== null) {
       result = basicResult
@@ -453,6 +459,10 @@ export const DEFAULT_OPTIONS: Options = {
   printFunctionName: true,
   printShadowRoot: true,
   theme: DEFAULT_THEME,
+  singleQuote: false,
+  quoteKeys: true,
+  spacingInner: '\n',
+  spacingOuter: '\n',
 } satisfies Options
 
 function validateOptions(options: OptionsReceived) {
@@ -525,11 +535,13 @@ function getConfig(options?: OptionsReceived): Config {
     maxWidth: options?.maxWidth ?? DEFAULT_OPTIONS.maxWidth,
     min: options?.min ?? DEFAULT_OPTIONS.min,
     plugins: options?.plugins ?? DEFAULT_OPTIONS.plugins,
-    printBasicPrototype: options?.printBasicPrototype ?? true,
+    printBasicPrototype: options?.printBasicPrototype ?? !options?.min,
     printFunctionName: getPrintFunctionName(options),
     printShadowRoot: options?.printShadowRoot ?? true,
-    spacingInner: options?.min ? ' ' : '\n',
-    spacingOuter: options?.min ? '' : '\n',
+    spacingInner: options?.spacingInner ?? (options?.min ? ' ' : '\n'),
+    spacingOuter: options?.spacingOuter ?? (options?.min ? '' : '\n'),
+    singleQuote: options?.singleQuote ?? DEFAULT_OPTIONS.singleQuote,
+    quoteKeys: options?.quoteKeys ?? DEFAULT_OPTIONS.quoteKeys,
     maxOutputLength: options?.maxOutputLength ?? DEFAULT_OPTIONS.maxOutputLength,
     _outputLengthPerDepth: [],
   }
@@ -547,25 +559,26 @@ function createIndent(indent: number): string {
 export function format(val: unknown, options?: OptionsReceived): string {
   if (options) {
     validateOptions(options)
-    if (options.plugins) {
-      const plugin = findPlugin(options.plugins, val)
-      if (plugin !== null) {
-        return printPlugin(plugin, val, getConfig(options), '', 0, [])
-      }
-    }
+  }
+
+  const config = getConfig(options)
+  const plugin = findPlugin(config.plugins, val)
+  if (plugin !== null) {
+    return printPlugin(plugin, val, config, '', 0, [])
   }
 
   const basicResult = printBasicValue(
     val,
-    getPrintFunctionName(options),
-    getEscapeRegex(options),
-    getEscapeString(options),
+    config.printFunctionName,
+    config.escapeRegex,
+    config.escapeString,
+    config.singleQuote,
   )
   if (basicResult !== null) {
     return basicResult
   }
 
-  return printComplexValue(val, getConfig(options), '', 0, [])
+  return printComplexValue(val, config, '', 0, [])
 }
 
 export type {