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

Configuration

Editors

Formatter

JavaScript APIs

Linter

Enhancements

noFallthroughSwitchClause reports most of invalid codes.

The rule now relies on control flow analysis and thus reports more complex case fallthrough.

Bug fixes

Fix #182, making useLiteralKeys retains optional chaining.

Parser

VSCode

1.1.2 (2023-09-07)

Editors

Bug fixes

Fixed a case where an empty JSON file would cause the LSP server to crash.

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";
```

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.

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.

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.

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.

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

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}\``;
```
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)
```
You can use // biome-ignore as suppression comment.
The // rome-ignore suppression is deprecated.
noUselessConstructor now ignores decorated classes and decorated parameters. The rule now gives suggestions instead of safe fixes when parameters are annotated with types.

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>
```
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++
) {}
```
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`
```

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.

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
```
Fix #106

noUndeclaredVariables now correctly recognizes some TypeScript types such as Uppercase.
Fix rome#4616

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

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.quifix.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:

a11y/useHeadingContent
complexity/noForEach
complexity/useLiteralKeys
complexity/useSimpleNumberKeys
correctness/useIsNan
suspicious/noConsoleLog
suspicious/noDuplicateJsxProps

The following rules are now recommended:

noUselessFragments
noRedundantUseStrict
useExponentiationOperator

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();
```

Files

CHANGELOG.md

Latest commit

History

CHANGELOG.md

File metadata and controls

Biome changelog

Unreleased

Analyzer

CLI

Configuration

Editors

Formatter

JavaScript APIs

Linter

Enhancements

Bug fixes

Parser

VSCode

1.1.2 (2023-09-07)

Editors

Bug fixes

Linter

Enhancements

1.1.1 (2023-09-07)

Analyzer

Bug fixes

1.1.0 (2023-09-06)

Analyzer

Enhancements

CLI

Enhancements

Bug fixes

Configuration

Editors

Bug fixes

Formatter

Enhancements

JavaScript APIs

Linter

Enhancements

Bug fixes

1.0.0 (2023-08-28)

Analyzer

BREAKING CHANGES

CLI

BREAKING CHANGES

Other changes

Configuration

Other changes

Editors

Other changes

Formatter

Linter

Removed rules

New rules

Promoted rules

Other changes

Parser