Biome changelog

This project follows Semantic Versioning. Due to the nature of Biome as a toolchain, it can be unclear what changes are considered major, minor, or patch. Read our guidelines to categorize a change.

New entries must be placed in a section entitled Unreleased. Read our guidelines for writing a good changelog entry.

Unreleased

Analyzer

CLI

Remove the CLI options from the lsp-proxy, as they were never meant to be passed to that command. Contributed by @ematipico
Add option --config-path to lsp-proxy and start commands. It's now possible to tell the Daemon server to load biome.json from a custom path. Contributed by @ematipico
Add new --diagnostic-level option to let users control the level of diagnostics printed by the CLI. Possible values are: "info", "warn", "hint". Contributed by @simonxabris

Bug fixes

Fix the command format, now it returns a non-zero exit code when if there pending diffs. Contributed by @ematipico

Configuration

Editors

Formatter

New features

Add a new option --line-ending. This option allows changing the type of line endings. Contributed by @SuperchupuDev
Added a new option called --bracket-spacing to the formatter. This option allows you to control whether spaces are inserted around the brackets of object literals. #627. Contributed by @faultyserver

Bug fixes

Fix #301, the formatter should not break before the in keyword. Contributed by @ematipico

JavaScript APIs

Linter

New features

Add noDefaultExport which disallows export default. Contributed by @Conaclos

Bug fixes

Fix #639 by ignoring unused TypeScript's mapped key. Contributed by @Conaclos
Fix #565 by handling several infer with the same name in extends clauses of TypeScript's conditional types. Contributed by @Conaclos
Fix #653. noUnusedImports now correctly removes the entire line where the unused import is. Contributed by @Conaclos
Fix #607 useExhaustiveDependencies, ignore optional chaining, Contributed by @msdlisper
Fix #676, by using the correct node for the "noreferrer" when applying the code action. Contributed by @ematipico
Fix #455. The CLI can now print complex emojis to the console correctly.
Fix #727. noInferrableTypes now correctly keeps type annotations when the initialization expression is null. Contributed by @Conaclos
Fix #784, noSvgWithoutTitle fixes false-positives to aria-label and reports svg's role attribute is implicit. Contributed by @unvalley

Parser

VSCode

1.3.3 (2023-10-31)

Analyzer

Bug fixes

Fix #604 which made noConfusingVoidType report false positives when the void type is used in a generic type parameter. Contributed by @unvalley

CLI

Bug fixes

Fix how overrides behave. Now ignore and include apply or not the override pattern, so they override each other. Now the options inside overrides override the top-level options.
Bootstrap the logger only when needed. Contributed by @ematipico
Fix how overrides are run. The properties ignore and include have different semantics and only apply/not apply an override. Contributed by @ematipico

Editors

Bug fixes

Fix #592, by changing binary resolution in the IntelliJ plugin. Contributed by @Joshuabaker2

Formatter

Bug fixes

Apply the correct layout when the right hand of an assignment expression is a await expression or a yield expression. Contributed by @ematipico
Fix #303, where nested arrow functions didn't break. Contributed by @victor-teles

Linter

Bug fixes

Fix #175 which made noRedeclare report index signatures using the name of a variable in the parent scope.
Fix #557 which made noUnusedImports report imported types used in typeof expression. Contributed by @Conaclos
Fix #576 by removing some erroneous logic in noSelfAssign. Contributed by @ematipico
Fix #595 by updating unsafe-apply logic to avoid unexpected errors in noUselessFragments. Contributed by @nissy-dev
Fix #591 which made noRedeclare report type parameters with identical names but in different method signatures. Contributed by @Conaclos
Support more a11y roles and fix some methods for a11y lint rules Contributed @nissy-dev
Fix #609 useExhaustiveDependencies, by removing useContext, useId and useSyncExternalStore from the known hooks. Contributed by @msdlisper
Fix useExhaustiveDependencies, by removing useContext, useId and useSyncExternalStore from the known hooks. Contributed by @msdlisper

New features

Add noUnusedPrivateClassMembers rule. The rule disallow unused private class members. Contributed by @victor-teles

Parser

Enhancements

Support RegExp v flag. Contributed by @nissy-dev
Improve error messages. Contributed by @ematipico

1.3.1 (2023-10-20)

CLI

Bug fixes

Fix rage command, now it doesn't print info about running servers. Contributed by @ematipico

Editors

Bug fixes

Fix #552, where the formatter isn't correctly triggered in Windows systems. Contributed by @victor-teles

Linter

New features

Add noThisInStatic rule. Contributed by @ditorodev and @Conaclos

Bug fixes

Fix #548 which made noSelfAssign panic.
Fix #555, by correctly map globals into the workspace.

1.3.0 (2023-10-19)

Analyzer

Enhancements

Import sorting is safe to apply now, and it will be applied when running check --apply instead of check --apply-unsafe.
Import sorting now handles Bun imports bun:<name>, absolute path imports /<path>, and Node's subpath imports #<name>. See our documentation for more details. Contributed by @Conaclos

CLI

Bug fixes

Fix #319. The command biome lint now shows the correct options. Contributed by @ematipico
Fix #312. Running biome --version now exits with status code 0 instead of 1. Contributed by @nhedger
Fix a bug where the extends functionality doesn't carry over organizeImports.ignore. Contributed by @ematipico
The CLI now returns the original content when using stdin and the original content doesn't change. Contributed by @ematipico

New features

Add support for BIOME_BINARY environment variable to override the location of the binary. Contributed by @ematipico
Add option --indent-width, and deprecated the option --indent-size. Contributed by @ematipico
Add option --javascript-formatter-indent-width, and deprecated the option --javascript-formatter-indent-size. Contributed by @ematipico
Add option --json-formatter-indent-width, and deprecated the option --json-formatter-indent-size. Contributed by @ematipico
Add option --daemon-logs to biome rage. The option is required to view Biome daemon server logs. Contributed by @unvalley

Add support for logging. By default, Biome doesn't log anything other than diagnostics. Logging can be enabled with the new option --log-level:

biome format --log-level=info ./src

There are four different levels of logging, from the most verbose to the least verbose: debug, info, warn and error. Here's how an INFO log will look like:

2023-10-05T08:27:01.954727Z  INFO  Analyze file ./website/src/playground/components/Resizable.tsx
  at crates/biome_service/src/file_handlers/javascript.rs:298 on biome::worker_5
  in Pulling diagnostics with categories: RuleCategories(SYNTAX)
  in Processes formatting with path: "./website/src/playground/components/Resizable.tsx"
  in Process check with path: "./website/src/playground/components/Resizable.tsx"

You can customize how the log will look like with a new option --log-kind. The supported kinds are: pretty, compact and json.

pretty is the default logging. Here's how a compact log will look like:

2023-10-05T08:29:04.864247Z  INFO biome::worker_2 Process check:Processes linting:Pulling diagnostics: crates/biome_service/src/file_handlers/javascript.rs: Analyze file ./website/src/playground/components/Resizable.tsx path="./website/src/playground/components/Resizable.tsx" path="./website/src/playground/components/Resizable.tsx" categories=RuleCategories(LINT)
2023-10-05T08:29:04.864290Z  INFO biome::worker_7 Process check:Processes formatting: crates/biome_service/src/file_handlers/javascript.rs: Format file ./website/src/playground/components/Tabs.tsx path="./website/src/playground/components/Tabs.tsx" path="./website/src/playground/components/Tabs.tsx"
2023-10-05T08:29:04.879332Z  INFO biome::worker_2 Process check:Processes formatting:Pulling diagnostics: crates/biome_service/src/file_handlers/javascript.rs: Analyze file ./website/src/playground/components/Resizable.tsx path="./website/src/playground/components/Resizable.tsx" path="./website/src/playground/components/Resizable.tsx" categories=RuleCategories(SYNTAX)
2023-10-05T08:29:04.879383Z  INFO biome::worker_2 Process check:Processes formatting: crates/biome_service/src/file_handlers/javascript.rs: Format file ./website/src/playground/components/Resizable.tsx path="./website/src/playground/components/Resizable.tsx" path="./website/src/playground/components/Resizable.tsx"

Enhancements

Deprecated the environment variable ROME_BINARY. Use BIOME_BINARY instead. Contributed by @ematipico
Biome doesn't check anymore the presence of the .git folder when VCS support is enabled. Contributed by @ematipico
biome rage doesn't print the logs of the daemon, use biome rage --daemon-logs to print them. Contributed by @unvalley

Configuration

New features

Add option formatter.indentWidth, and deprecated the option formatter.indentSize. Contributed by @ematipico
Add option javascript.formatter.indentWidth, and deprecated the option javascript.formatter.indentSize. Contributed by @ematipico
Add option json.formatter.indentWidth, and deprecated the option json.formatter.indentSize. Contributed by @ematipico
Add option include to multiple sections of the configuration
- files.include;
- formatter.include;
- linter.include;
- organizeImports.include; When include and ignore are both specified, ignore takes precedence over include

Add option overrides, where users can modify the behaviour of the tools for certain files or paths.

For example, it's possible to modify the formatter lineWidth, and even quoteStyle for certain files that are included in glob path generated/**:

{
  "formatter": {
    "lineWidth": 100
  },
  "overrides": [
    {
      "include": ["generated/**"],
      "formatter": {
        "lineWidth": 160
      },
      "javascript": {
        "formatter": {
          "quoteStyle": "single"
        }
      }
    }
  ]
}

Or, you can disable certain rules for certain path, and disable the linter for other paths:

{
  "linter": {
    "enabled": true,
    "rules": {
      "recommended": true
    }
  },
  "overrides": [
    {
      "include": ["lib/**"],
      "linter": {
        "rules": {
          "suspicious": {
            "noDebugger": "off"
          }
        }
      }
    },
    {
      "include": ["shims/**"],
      "linter": {
        "enabled": false
      }
    }
  ]
}

Bug fixes

Fix #343, extends was incorrectly applied to the biome.json file. Contributed by @ematipico

Editors

Bug fixes

Fix #404. Biome intellij plugin now works on Windows. Contributed by @victor-teles
Fix #402. Biome format on intellij plugin now recognize biome.json. Contributed by @victor-teles

Formatter

Enhancements

Use OnceCell for the Memoized memory because that's what the RefCell<Option> implemented. Contributed by @denbezrukov

Linter

Promoted rules

The following rules are now recommended:

New features

Add noEmptyCharacterClassInRegex rule. The rule reports empty character classes and empty negated character classes in regular expression literals. Contributed by @Conaclos
Add noMisleadingInstantiator rule. The rule reports the misleading use of the new and constructor methods. Contributed by @unvalley
Add noUselessElse rule. The rule reports else clauses that can be omitted because their if branches break. Contributed by @Conaclos
Add noUnusedImports rule. The rule reports unused imports and suggests to remove them. Contributed by @Conaclos

noUnusedVariables reports also unused imports, but don't suggest their removal. Once noUnusedImports stabilized, noUnusedVariables will not report unused imports.
Add useShorthandAssign rule. The rule enforce use of shorthand operators that combine variable assignment and some simple mathematical operations. For example, x = x + 4 can be shortened to x += 4. Contributed by @victor-teles
Add useAsConstAssertion rule. The rule enforce use of as const assertion to infer literal types. Contributed by @unvalley
Add noMisrefactoredShorthandAssign rule. The rule reports shorthand assigns when variable appears on both sides. For example x += x + b Contributed by @victor-teles
Add noApproximativeNumericConstant rule. Contributed by @nikeee
Add noInteractiveElementToNoninteractiveRole rule. The rule enforces the non-interactive ARIA roles are not assigned to interactive HTML elements. Contributed by @nissy-dev
Add useAriaActivedescendantWithTabindex rule. The rule enforces that tabIndex is assigned to non-interactive HTML elements with aria-activedescendant. Contributed by @nissy-dev
Add noUselessLoneBlockStatements rule. The rule reports standalone blocks that don't include any lexical scoped declaration. Contributed by @emab
Add noInvalidNewBuiltin rule. The rule reports use of new on Symbol and BigInt. Contributed by @lucasweng

Enhancements

The following rules have now safe code fixes:
noAccumulatingSpread makes more check in order to reduce potential false positives. Contributed by @Vivalldi
noConstAssign now provides an unsafe code fix that replaces const with let. Contributed by @vasucp1207
noExcessiveComplexity default complexity threshold is now 15. Contributed by @arendjr
noPositiveTabindexValue now provides an unsafe code fix that set to 0 the tab index. Contributed by @vasucp1207
noUnusedLabels no longer reports unbreakable labeled statements. Contributed by @Conaclos
noUnusedVariables now reports unused TypeScript's type parameters. Contributed by @Conaclos
useAnchorContent now provides an unsafe code fix that removes the `aria-hidden`` attribute. Contributed by @vasucp1207
useValidAriaProps now provides an unsafe code fix that removes invalid properties. Contributed by @vasucp1207
noExcessiveComplexity was renamed to noExcessiveCognitiveComplexity

Bug fixes

Fix #294. noConfusingVoidType no longer reports false positives for return types. Contributed by @b4s36t4
Fix #313. noRedundantUseStrict now keeps leading comments.
Fix #383. noMultipleSpacesInRegularExpressionLiterals now provides correct code fixes when consecutive spaces are followed by a quantifier. Contributed by @Conaclos
Fix #397. useNumericLiterals now provides correct code fixes for signed numbers. Contributed by @Conaclos
Fix 452. The linter panicked when it met a malformed regex (a regex not ending with a slash).
Fix #104. We now correctly handle types and values with the same name.
Fix #243 a false positive case where the incorrect scope was defined for the infer type. in rule noUndeclaredVariables. Contributed by @denbezrukov
Fix #322, now noSelfAssign correctly handles literals inside call expressions.
Changed how noSelfAssign behaves. The rule is not triggered anymore on function calls. Contributed by @ematipico

Parser

Enhance diagnostic for infer type handling in the parser. The 'infer' keyword can only be utilized within the 'extends' clause of a conditional type. Using it outside of this context will result in an error. Ensure that any type declarations using 'infer' are correctly placed within the conditional type structure to avoid parsing issues. Contributed by @denbezrukov

Add support for parsing trailing commas inside JSON files:

{
  "json": {
    "parser": {
      "allowTrailingCommas": true
    }
  }
}

Contributed by @nissy-dev

VSCode

1.2.2 (2023-09-16)

CLI

Bug fixes

Fix a condition where import sorting wasn't applied when running biome check --apply

1.2.1 (2023-09-15)

Configuration

Fix an edge case where the formatter language configuration wasn't picked.
Fix the configuration schema, where json.formatter properties weren't transformed in camel case.

1.2.0 (2023-09-15)

CLI

New features

Add new options to customize the behaviour the formatter based on the language of the file
- --json-formatter-enabled
- --json-formatter-indent-style
- --json-formatter-indent-size
- --json-formatter-line-width
- --javascript-formatter-enabled
- --javascript-formatter-indent-style
- --javascript-formatter-indent-size
- --javascript-formatter-line-width

Bug fixes

Fix a bug where --errors-on-warning didn't work when running biome ci command.

Configuration

New features

Add new options to customize the behaviour of the formatter based on the language of the file
- json.formatter.enabled
- json.formatter.indentStyle
- json.formatter.indentSize
- json.formatter.lineWidth
- javascript.formatter.enabled
- javascript.formatter.indentStyle
- javascript.formatter.indentSize
- javascript.formatter.lineWidth

Linter

Promoted rules

New rules are incubated in the nursery group. Once stable, we promote them to a stable group. The following rules are promoted:

New rules

Add noConfusingVoidType rule. The rule reports the unusual use of the void type. Contributed by @shulandmimi

Removed rules

Remove noConfusingArrow.

Code formatters, such as prettier and Biome, always adds parentheses around the parameter or the body of an arrow function. This makes the rule useless.

Contributed by @Conaclos

Enhancements

noFallthroughSwitchClause now relies on control flow analysis to report most of switch clause fallthrough. Contributed by @Conaclos
noAssignInExpressions no longer suggest code fixes. Most of the time the suggestion didn't match users' expectations. Contributed by @Conaclos
noUselessConstructor no longer emits safe code fixes. Contributed by @Conaclos

All code fixes are now emitted as unsafe code fixes. Removing a constructor can change the behavior of a program.
useCollapsedElseIf now only provides safe code fixes. Contributed by @Conaclos
noUnusedVariables now reports more cases.

The rule is now able to ignore self-writes. For example, the rule reports the following unused variable:
```
let a = 0;
a++;
a += 1;
```
The rule is also capable of detecting an unused declaration that uses itself. For example, the rule reports the following unused interface:
```
interface I {
  instance(): I
}
```
Finally, the rule now ignores all TypeScript declaration files, including global declaration files.

Contributed by @Conaclos

Bug fixes

Fix #182, making useLiteralKeys retains optional chaining. Contributed by @denbezrukov
Fix #168, fix useExhaustiveDependencies false positive case when stable hook is on a new line. Contributed by @denbezrukov

Fix #137, fix noRedeclare false positive case with TypeScript module declaration:

declare module '*.gif' {
    const src: string;
}

declare module '*.bmp' {
    const src: string;
}

Contributed by @denbezrukov

Fix #258, fix noUselessFragments the case where the rule removing an assignment. Contributed by @denbezrukov
Fix #266, where complexity/useLiteralKeys emitted a code action with an invalid AST. Contributed by @ematipico
Fix #105, removing false positives reported by noUnusedVariables.

The rule no longer reports the following used variable:
```
const a = f(() => a);
```
Contributed by @Conaclos

VSCode

Enhancements

Improve server binary resolution when using certain package managers, notably pnpm.

The new strategy is to point to node_modules/.bin/biome path, which is consistent for all package managers.

1.1.2 (2023-09-07)

Editors

Bug fixes

Fix a case where an empty JSON file would cause the LSP server to crash. Contributed by @ematipico

Linter

Enhancements

useNamingConvention now accepts import namespaces in PascalCase and rejects export namespaces in CONSTANT_CASE.

The following code is now valid:
```
import * as React from "react";
```
And the following code is now invalid:
```
export * as MY_NAMESPACE from "./lib.js";
```
Contributed by @Conaclos
noUselessConstructor now ignores decorated classes and decorated parameters. The rule now gives suggestions instead of safe fixes when parameters are annotated with types. Contributed by @Conaclos

1.1.1 (2023-09-07)

Analyzer

Bug fixes

The diagnostic for // rome-ignore suppression comment should not be a warning. A warning could block the CI, marking a gradual migration difficult. The code action that changes // rome-ignore to // biome-ignore is disabled as consequence. Contributed by @ematipico

1.1.0 (2023-09-06)

Analyzer

Enhancements

Add a code action to replace rome-ignore with biome-ignore. Use biome check --apply-unsafe to update all the comments. The action is not bulletproof, and it might generate unwanted code, that's why it's unsafe action. Contributed by @ematipico

CLI

Enhancements

Biome now reports a diagnostics when a rome.json file is found.
biome migrate --write creates biome.json from rome.json, but it won't delete the rome.json file. Contributed by @ematipico

Bug fixes

Biome uses biome.json first, then it attempts to use rome.json.
Fix a case where Biome couldn't compute correctly the ignored files when the VSC integration is enabled. Contributed by @ematipico

Configuration

Editors

Bug fixes

The LSP now uses its own socket and won't rely on Biome's socket. This fixes some cases where users were seeing multiple servers in the rage output.

Formatter

Enhancements

You can use // biome-ignore as suppression comment.
The // rome-ignore suppression is deprecated.

JavaScript APIs

Linter

New features

Add useCollapsedElseIf rule. This new rule requires merging an else and an if, if the if statement is the only statement in the else block. Contributed by @n-gude

Enhancements

useTemplate now reports all string concatenations.

Previously, the rule ignored concatenation of a value and a newline or a backquote. For example, the following concatenation was not reported:
```
v + "\n";
"`" + v + "`";
```
The rule now reports these cases and suggests the following code fixes:
```
- v + "\n";
+ `${v}\n`;
- v + "`";
+ `\`${v}\``;
```
Contributed by @Conaclos
useExponentiationOperator suggests better code fixes.

The rule now preserves any comment preceding the exponent, and it preserves any parenthesis around the base or the exponent. It also adds spaces around the exponentiation operator **, and always adds parentheses for pre- and post-updates.
```
- Math.pow(a++, /**/ (2))
+ (a++) ** /**/ (2)
```
Contributed by @Conaclos
You can use // biome-ignore as suppression comment.
The // rome-ignore suppression is deprecated.

Bug fixes

Fix #80, making noDuplicateJsxProps case-insensitive.

Some frameworks, such as Material UI, rely on the case-sensitivity of JSX properties. For example, TextField has two properties with the same name, but distinct cases:
```
<TextField inputLabelProps="" InputLabelProps=""></TextField>
```
Contributed by @Conaclos
Fix #138

noCommaOperator now correctly ignores all use of comma operators inside the update part of a for loop. The following code is now correctly ignored:
```
for (
  let i = 0, j = 1, k = 2;
  i < 100;
  i++, j++, k++
) {}
```
Contributed by @Conaclos
Fix rome#4713.

Previously, useTemplate made the following suggestion:
```
- a + b + "px"
+ `${a}${b}px`
```
This breaks code where a and b are numbers.

Now, the rule makes the following suggestion:
```
- a + b + "px"
+ `${a + b}px`
```
Contributed by @Conaclos

Fix rome#4109

Previously, useTemplate suggested an invalid code fix when a leading or trailing single-line comment was present:

  // leading comment
- 1 /* inner comment */ + "+" + 2 // trailing comment
+ `${// leading comment
+ 1 /* inner comment */}+${2 //trailing comment}` // trailing comment

Now, the rule correctly handle this case:

  // leading comment
- 1 + "+" + 2 // trailing comment
+ `${1}+${2}` // trailing comment

As a sideeffect, the rule also suggests the removal of any inner comments.

Contributed by @Conaclos

Fix rome#3850

Previously useExponentiationOperator suggested invalid code in a specific edge case:
```
- 1 +Math.pow(++a, 2)
+ 1 +++a**2
```
Now, the rule properly adds parentheses:
```
- 1 +Math.pow(++a, 2)
+ 1 +(++a) ** 2
```
Contributed by @Conaclos
Fix #106

noUndeclaredVariables now correctly recognizes some TypeScript types such as Uppercase.

Contributed by @Conaclos
Fix rome#4616

Previously noUnreachableSuper reported valid codes with complex nesting of control flow structures.

Contributed by @Conaclos

1.0.0 (2023-08-28)

Analyzer

BREAKING CHANGES

The organize imports feature now groups import statements by "distance".

Modules "farther" from the user are put on the top, and modules "closer" to the user are placed on the bottom. Check the documentation for more information about it.
The organize imports tool is enabled by default. If you don't want to use it, you need to disable it explicitly:
```
{
  "organizeImports": {
    "enabled": false
  }
}
```

CLI

BREAKING CHANGES

The CLI now exists with an error when there's an error inside the configuration.

Previously, biome would raise warnings and continue the execution by applying its defaults.

This could have been better for users because this could have created false positives in linting or formatted code with a configuration that wasn't the user's.
The command biome check now shows formatter diagnostics when checking the code.

The diagnostics presence will result in an error code when the command finishes.

This aligns with semantic and behaviour meant for the command biome check.
init command emits a biome.json file;

Other changes

Fix #4670, don't crash at empty default export.
Fix #4556, which correctly handles new lines in the .gitignore file across OS.
Add a new option to ignore unknown files --files-ignore-unknown:
```
biome format --files-ignore-unknown ./src
```
Doing so, Biome won't emit diagnostics for files that doesn't know how to handle.
Add the new option --no-errors-on-unmatched:
```
biome format --no-errors-on-unmatched ./src
```
Biome doesn't exit with an error code if no files were processed in the given paths.
Fix the diagnostics emitted when running the biome format command.
Biome no longer warns when discovering (possibly infinite) symbolic links between directories.

This fixes #4193 which resulted in incorrect warnings when a single file or directory was pointed at by multiple symbolic links. Symbolic links to other symbolic links do still trigger warnings if they are too deeply nested.
Introduced a new command called biome lint, which will only run lint rules against the code base.
Biome recognises known files as "JSON files with comments allowed":
- typescript.json;
- tsconfig.json;
- jsconfig.json;
- tslint.json;
- babel.config.json;
- .babelrc.json;
- .ember-cli;
- typedoc.json;
- .eslintrc.json;
- .eslintrc;
- .jsfmtrc;
- .jshintrc;
- .swcrc;
- .hintrc;
- .babelrc;
Add support for biome.json;

Configuration

Other changes

Add a new option to ignore unknown files:
```
{
   "files": {
      "ignoreUnknown": true
   }
}
```
Doing so, Biome won't emit diagnostics for file that it doesn't know how to handle.

Add a new "javascript" option to support the unsafe/experimental parameter decorators:

{
   "javascript": {
      "parser": {
         "unsafeParameterDecoratorsEnabled": true
      }
   }
}

Add a new "extends" option, useful to split the configuration file in multiple files:
```
{
  "extends": ["../sharedFormatter.json", "linter.json"]
}
```
The resolution of the files is file system based, Biome doesn't know how to resolve dependencies yet.
The commands biome check and biome lint now show the remaining diagnostics even when --apply-safe or --apply-unsafe are passed.
Fix the commands biome check and biome lint, they won't exit with an error code if no error diagnostics are emitted.
Add a new option --error-on-warnings, which instructs Biome to exit with an error code when warnings are emitted.
```
biome check --error-on-wanrings ./src
```

Add a configuration to enable parsing comments inside JSON files:

{
  "json": {
    "parser": {
      "allowComments": true
    }
  }
}

Editors

Other changes

The Biome LSP can now show diagnostics belonging to JSON lint rules.
The Biome LSP no longer applies unsafe quickfixes on-save when editor.codeActionsOnSave.quickfix.biome is enabled.
Fix #4564; files too large don't emit errors.
The Biome LSP sends client messages when files are ignored or too big.

Formatter

Add a new option called --jsx-quote-style.

This option lets you choose between single and double quotes for JSX attributes.
Add the option --arrow-parentheses.

This option allows setting the parentheses style for arrow functions.
The JSON formatter can now format .json files with comments.

Linter

Removed rules

Remove complexity/noExtraSemicolon (#4553)

The Biome formatter takes care of removing extra semicolons. Thus, there is no need for this rule.
Remove useCamelCase

Use useNamingConvention instead.

New rules

Add noExcessiveComplexity
Add useImportRestrictions
Add noFallthroughSwitchClause
Add noGlobalIsFinite

This rule recommends using Number.isFinite instead of the global and unsafe isFinite that attempts a type coercion.
Add noGlobalIsNan

This rule recommends using Number.isNaN instead of the global and unsafe isNaN that attempts a type coercion.
Add noUnsafeDeclarationMerging

This rule disallows declaration merging between an interface and a class.
Add noUselessThisAlias

This rule disallows useless aliasing of this in arrow functions.
Add useArrowFunction

This rule proposes turning function expressions into arrow functions. Function expressions that use this are ignored.
Add noDuplicateJsonKeys

This rule disallow duplicate keys in a JSON object.
Add noVoid

This rules disallow the use of void.
Add noNonoctalDecimalEscape

This rule disallows \8 and \9 escape sequences in string literals.
Add noUselessEmptyExport

This rule disallows useless export {}.
Add useIsArray

This rule proposes using Array.isArray() instead of instanceof Array.
Add useGetterReturn

This rule enforces the presence of non-empty return statements in getters. This makes the following code incorrect:
```
class Person {
    get firstName() {}
}
```

Promoted rules

New rules are promoted, please check #4750 for more details:

The following rules are now recommended:

**- noUselessFragments

Other changes

Add new TypeScript globals (AsyncDisposable, Awaited, DecoratorContext, and others) 4643.
noRedeclare: allow redeclare of index signatures are in different type members #4478
Improve noConsoleLog, noGlobalObjectCalls, useIsNan, and useNumericLiterals by handling globalThis and window namespaces.

For instance, the following code is now reported by noConsoleLog:
```
globalThis.console.log("log")
```
Improve noDuplicateParameters to manage constructor parameters.
Improve noInnerDeclarations

Now, the rule doesn't report false-positives about ambient TypeScript declarations. For example, the following code is no longer reported by the rule:
```
declare var foo;
```
Improve useEnumInitializers

The rule now reports all uninitialized members of an enum in a single diagnostic.

Moreover, ambient enum declarations are now ignored. This avoids reporting ambient enum declarations in TypeScript declaration files.
```
declare enum Weather {
  Rainy,
  Sunny,
}
```
Relax noBannedTypes and improve documentation

The rule no longer reports a user type that reuses a banned type name. The following code is now allowed:
```
import { Number } from "a-lib";
declare const v: Number;
```
The rule now allows the use of the type {} to denote a non-nullable generic type:
```
function f<T extends {}>(x: T) {
    assert(x != null);
}
```
And in a type intersection for narrowing a type to its non-nullable equivalent type:
```
type NonNullableMyType = MyType & {};
```
Improve noConstantCondition

The rule now allows while(true). This recognizes a common pattern in the web community:
```
while (true) {
  if (cond) {
    break;
  }
}
```
Improve the diagnostic and the code action of useDefaultParameterLast.

The diagnostic now reports the last required parameter which should precede optional and default parameters.

The code action now removes any whitespace between the parameter name and its initialization.
Relax noConfusingArrow

All arrow functions that enclose its parameter with parenthesis are allowed. Thus, the following snippet no longer trigger the rule:
```
var x = (a) => 1 ? 2 : 3;
```
The following snippet still triggers the rule:
```
var x = a => 1 ? 2 : 3;
```
Relax useLiteralEnumMembers

Enum members that refer to previous enum members are now allowed. This allows a common pattern in enum flags like in the following example:
```
enum FileAccess {
  None = 0,
  Read = 1,
  Write = 1 << 1,
  All = Read | Write,
}
```
Arbitrary numeric constant expressions are also allowed:
```
enum FileAccess {
  None = 0,
  Read = 2**0,
  Write = 2**1,
  All = Read | Write,
}
```
Improve useLiteralKeys.

Now, the rule suggests simplifying computed properties to string literal properties:
```
{
-  ["1+1"]: 2,
+  "1+1": 2,
}
```
It also suggests simplifying string literal properties to static properties:
```
{
-  "a": 0,
+  a: 0,
}
```
These suggestions are made in object literals, classes, interfaces, and object types.
Improve noNewSymbol.

The rule now handles cases where Symbol is namespaced with the global globalThis or window.

The rules useExhaustiveDependencies and useHookAtTopLevel accept a different shape of options

Old configuration:

{
  "linter": {
     "rules": {
        "nursery": {
           "useExhaustiveDependencies": {
              "level": "error",
              "options": {
                 "hooks": [
                    ["useMyEffect", 0, 1]
                 ]
              }
           }
        }
     }
  }
}

New configuration:

{
  "linter": {
     "rules": {
        "nursery": {
           "useExhaustiveDependencies": {
              "level": "error",
              "options": {
                 "hooks": [
                    {
                       "name": "useMyEffect",
                       "closureIndex": 0,
                       "dependenciesIndex": 1
                    }
                 ]
              }
           }
        }
     }
  }
}

noRedundantUseStrict check only 'use strict' directive to resolve false positive diagnostics.

React introduced new directives, "use client" and "use server". The rule raises false positive errors about these directives.
Fix a crash in the NoParameterAssign rule that occurred when there was a bogus binding. #4323
Fix useExhaustiveDependencies in the following cases #4330:
- when the first argument of hooks is a named function
- inside an export default function
- for React.use* hooks
Fix noInvalidConstructorSuper that erroneously reported generic parents #4624.
Fix noDuplicateCase that erroneously reported as equals the strings literals "'" and '"' #4706.
Fix NoUnreachableSuper's false positive diagnostics (#4483) caused to nested if statement.

The rule no longer reports This constructor calls super() in a loop when using nested if statements in a constructor.
Fix useHookAtTopLevel's false positive diagnostics (#4637)

The rule no longer reports false positive diagnostics when accessing properties directly from a hook and calling a hook inside function arguments.
Fix noUselessConstructor which erroneously reported constructors with default parameters rome#4781
Fix noUselessFragments's panics when running biome check --apply-unsafe (#4637)

This rule's code action emits an invalid AST, so I fixed using JsxString instead of JsStringLiteral
Fix noUndeclaredVariables's false positive diagnostics (#4675)

The semantic analyzer no longer handles this reference identifier.
Fix noUnusedVariables's false positive diagnostics (#4688)

The semantic analyzer handles ts export declaration clause correctly.

Parser

Add support for decorators in class method parameters, example:

class AppController {
   get(@Param() id) {}
   // ^^^^^^^^ new supported syntax
}

This syntax is only supported via configuration, because it's a non-standard syntax.

{
   "javascript": {
      "parser": {
         "unsafeParameterDecoratorsEnabled": true
      }
   }
}

Add support for parsing comments inside JSON files:

{
  "json": {
    "parser": {
      "allowComments": true
    }
  }
}

Add support for the new using syntax
```
const using = resource.lock();
```

Uh oh!

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