Environment information
CLI:
Version: 2.2.4
Color support: true
Platform:
CPU Architecture: aarch64
OS: macos
Environment:
BIOME_LOG_PATH: unset
BIOME_LOG_PREFIX_NAME: unset
BIOME_CONFIG_PATH: unset
BIOME_THREADS: unset
NO_COLOR: unset
TERM: xterm-kitty
JS_RUNTIME_VERSION: v18.20.2
JS_RUNTIME_NAME: node
NODE_PACKAGE_MANAGER: unset
Biome Configuration:
Status: Loaded successfully
Path: biome.json
Formatter enabled: true
Linter enabled: true
Assist enabled: true
VCS enabled: true
Linter:
JavaScript enabled: unset
JSON enabled: unset
CSS enabled: unset
GraphQL enabled: unset
Recommended: true
Enabled rules:
a11y/noAccessKey
a11y/noAriaHiddenOnFocusable
a11y/noAriaUnsupportedElements
a11y/noDistractingElements
a11y/noHeaderScope
a11y/noInteractiveElementToNoninteractiveRole
a11y/noNoninteractiveElementToInteractiveRole
a11y/noNoninteractiveTabindex
a11y/noPositiveTabindex
a11y/noRedundantAlt
a11y/noRedundantRoles
a11y/useAltText
a11y/useAriaActivedescendantWithTabindex
a11y/useGenericFontNames
a11y/useHtmlLang
a11y/useIframeTitle
a11y/useKeyWithMouseEvents
a11y/useMediaCaption
a11y/useValidAriaProps
a11y/useValidAriaRole
a11y/useValidAriaValues
a11y/useValidAutocomplete
a11y/useValidLang
complexity/noAdjacentSpacesInRegex
complexity/noArguments
complexity/noBannedTypes
complexity/noCommaOperator
complexity/noEmptyTypeParameters
complexity/noExtraBooleanCast
complexity/noFlatMapIdentity
complexity/noStaticOnlyClass
complexity/noThisInStatic
complexity/noUselessCatch
complexity/noUselessConstructor
complexity/noUselessContinue
complexity/noUselessEmptyExport
complexity/noUselessEscapeInRegex
complexity/noUselessFragments
complexity/noUselessLabel
complexity/noUselessLoneBlockStatements
complexity/noUselessRename
complexity/noUselessStringRaw
complexity/noUselessTernary
complexity/noUselessThisAlias
complexity/noUselessTypeConstraint
complexity/useFlatMap
complexity/useIndexOf
complexity/useNumericLiterals
complexity/useRegexLiterals
complexity/useSimpleNumberKeys
correctness/noChildrenProp
correctness/noConstAssign
correctness/noConstantCondition
correctness/noConstantMathMinMaxClamp
correctness/noConstructorReturn
correctness/noEmptyCharacterClassInRegex
correctness/noEmptyPattern
correctness/noGlobalObjectCalls
correctness/noInnerDeclarations
correctness/noInvalidBuiltinInstantiation
correctness/noInvalidConstructorSuper
correctness/noInvalidDirectionInLinearGradient
correctness/noInvalidGridAreas
correctness/noInvalidPositionAtImportRule
correctness/noInvalidUseBeforeDeclaration
correctness/noMissingVarFunction
correctness/noNonoctalDecimalEscape
correctness/noPrecisionLoss
correctness/noSelfAssign
correctness/noSetterReturn
correctness/noStringCaseMismatch
correctness/noSwitchDeclarations
correctness/noUnknownFunction
correctness/noUnknownMediaFeatureName
correctness/noUnknownProperty
correctness/noUnknownPseudoClass
correctness/noUnknownPseudoElement
correctness/noUnknownTypeSelector
correctness/noUnknownUnit
correctness/noUnmatchableAnbSelector
correctness/noUnreachable
correctness/noUnreachableSuper
correctness/noUnsafeFinally
correctness/noUnsafeOptionalChaining
correctness/noUnusedFunctionParameters
correctness/noUnusedImports
correctness/noUnusedLabels
correctness/noUnusedPrivateClassMembers
correctness/noUnusedVariables
correctness/noVoidElementsWithChildren
correctness/noVoidTypeReturn
correctness/useExhaustiveDependencies
correctness/useGraphqlNamedOperations
correctness/useIsNan
correctness/useValidForDirection
correctness/useValidTypeof
correctness/useYield
performance/noDynamicNamespaceImportAccess
security/noBlankTarget
security/noDangerouslySetInnerHtml
security/noDangerouslySetInnerHtmlWithChildren
security/noGlobalEval
style/noDescendingSpecificity
style/noInferrableTypes
style/noNamespace
style/noRestrictedGlobals
style/noRestrictedImports
style/useArrayLiterals
style/useAsConstAssertion
style/useConst
style/useDeprecatedReason
style/useExponentiationOperator
style/useExportType
style/useImportType
style/useLiteralEnumMembers
style/useShorthandFunctionType
suspicious/noApproximativeNumericConstant
suspicious/noAsyncPromiseExecutor
suspicious/noBiomeFirstException
suspicious/noCatchAssign
suspicious/noClassAssign
suspicious/noCommentText
suspicious/noCompareNegZero
suspicious/noConfusingLabels
suspicious/noConfusingVoidType
suspicious/noConsole
suspicious/noConstEnum
suspicious/noControlCharactersInRegex
suspicious/noDebugger
suspicious/noDocumentCookie
suspicious/noDoubleEquals
suspicious/noDuplicateAtImportRules
suspicious/noDuplicateCase
suspicious/noDuplicateClassMembers
suspicious/noDuplicateCustomProperties
suspicious/noDuplicateElseIf
suspicious/noDuplicateFields
suspicious/noDuplicateFontNames
suspicious/noDuplicateJsxProps
suspicious/noDuplicateObjectKeys
suspicious/noDuplicateParameters
suspicious/noDuplicateProperties
suspicious/noDuplicateSelectorsKeyframeBlock
suspicious/noEmptyBlock
suspicious/noEmptyInterface
suspicious/noExplicitAny
suspicious/noExtraNonNullAssertion
suspicious/noFallthroughSwitchClause
suspicious/noFunctionAssign
suspicious/noGlobalAssign
suspicious/noImportAssign
suspicious/noImportantInKeyframe
suspicious/noIrregularWhitespace
suspicious/noLabelVar
suspicious/noMisleadingCharacterClass
suspicious/noMisleadingInstantiator
suspicious/noMisrefactoredShorthandAssign
suspicious/noOctalEscape
suspicious/noQuickfixBiome
suspicious/noRedeclare
suspicious/noRedundantUseStrict
suspicious/noShorthandPropertyOverrides
suspicious/noSparseArray
suspicious/noSuspiciousSemicolonInJsx
suspicious/noTemplateCurlyInString
suspicious/noTsIgnore
suspicious/noUnsafeDeclarationMerging
suspicious/noUnsafeNegation
suspicious/noUselessEscapeInString
suspicious/noUselessRegexBackrefs
suspicious/noWith
suspicious/useAdjacentOverloadSignatures
suspicious/useBiomeIgnoreFolder
suspicious/useDefaultSwitchClauseLast
suspicious/useGetterReturn
suspicious/useGoogleFontDisplay
suspicious/useNamespaceKeyword
Workspace:
Open Documents: 0Rule name
lint/complexity/useOptionalChain
Playground link
https://biomejs.dev/playground/?lintRules=useOptionalChain&analyzerFixMode=safeAndUnsafeFixes&code=YwBvAG4AcwBvAGwAZQAuAGwAbwBnACgAdAB5AHAAZQBvAGYAIAB3AGkAbgBkAG8AdwAgACEAPQA9ACAAIgB1AG4AZABlAGYAaQBuAGUAZAAiACAAJgAmACAAdwBpAG4AZABvAHcALgBsAG8AYwBhAHQAaQBvAG4AKQA7AAoA&language=ts
Expected result
The following snippets of code are not equivalent:
typeof window !== "undefined" && window.location
They are obviously inequivalent in the sense that the first can give false while the second can give undefined. This does not matter in practice, so I'm happy to apply the unsafe fix for the rule for local variables.
The issue is with global variables. The above snippets are essentially equivalent when run in a browser. But when run on a server (code like the above is very common in server-side React), the first one will return false while the second will throw a ReferenceError.
Suggestion: allow configuring a list of variable names (e.g. ["document", "window"]) not to apply the fix to
Code of Conduct
Environment information
Rule name
lint/complexity/useOptionalChain
Playground link
https://biomejs.dev/playground/?lintRules=useOptionalChain&analyzerFixMode=safeAndUnsafeFixes&code=YwBvAG4AcwBvAGwAZQAuAGwAbwBnACgAdAB5AHAAZQBvAGYAIAB3AGkAbgBkAG8AdwAgACEAPQA9ACAAIgB1AG4AZABlAGYAaQBuAGUAZAAiACAAJgAmACAAdwBpAG4AZABvAHcALgBsAG8AYwBhAHQAaQBvAG4AKQA7AAoA&language=ts
Expected result
The following snippets of code are not equivalent:
They are obviously inequivalent in the sense that the first can give
falsewhile the second can giveundefined. This does not matter in practice, so I'm happy to apply the unsafe fix for the rule for local variables.The issue is with global variables. The above snippets are essentially equivalent when run in a browser. But when run on a server (code like the above is very common in server-side React), the first one will return
falsewhile the second will throw aReferenceError.Suggestion: allow configuring a list of variable names (e.g.
["document", "window"]) not to apply the fix toCode of Conduct