Version History

Version 2.1.0

Minor Changes

#6512 0c0bf82 Thanks @arendjr! - The rule noFloatingPromises can now detect floating arrays of Promises.

Invalid examples

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// This gets flagged because the Promises are not handled.
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[1, 2, 3].map(async (x) => x + 1);

Valid examples

1
await Promise.all([1, 2, 3].map(async (x) => x + 1));

#6637 6918085 Thanks @arendjr! - Type inference is now able to handle the sequence operator ( ,), as well as post- and pre-update operators: ++.

Example

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let x = 5;
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// We now infer that `x++` resolves to a number, while the expression as a whole
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// becomes a Promise:
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(x++, new Promise((resolve) => resolve("comma")));

#6752 c9eaca4 Thanks @arendjr! - Fixed #6646: .gitignore files are now picked up even when running Biome from a nested directory, or when the ignore file itself is ignored through files.includes.
#6746 90aeead Thanks @arendjr! - biome migrate no longer enables style rules that were recommended in v1, because that would be undesirable for users upgrading from 2.0.

Users who are upgrading from Biome 1.x are therefore advised to first upgrade to Biome 2.0, and run the migration, before continuing to Biome 2.1 or later.

#6583 d415a3f Thanks @arendjr! - Added the nursery rule noMisusedPromises.

It signals Promises in places where conditionals or iterables are expected.

Invalid examples

1
const promise = Promise.resolve("value");
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// Using a `Promise` as conditional is always truthy:
4
if (promise) {
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  /* ... */
6
}
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// Spreading a `Promise` has no effect:
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console.log({ foo: 42, ...promise });
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// This does not `await` the `Promise`s from the callbacks,
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// so it does not behave as you may expect:
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[1, 2, 3].forEach(async (value) => {
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  await fetch(`/${value}`);
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});

Valid examples

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const promise = Promise.resolve("value");
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if (await promise) {
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  /* ... */
5
}
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console.log({ foo: 42, ...(await promise) });

#6405 cd4a9bb Thanks @vladimir-ivanov! - Added the ignoreRestSiblings option to the noUnusedFunctionParameters rule.

This option is used to ignore unused function parameters that are siblings of the rest parameter.

The default is false, which means that unused function parameters that are siblings of the rest parameter will be reported.

Example
```
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{
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  "rules": {
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    "noUnusedFunctionParameters": ["error", { "ignoreRestSiblings": true }]
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  }
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}
```
#6614 0840021 Thanks @arendjr! - We have implemented a more targeted version of the scanner, which ensures that if you provide file paths to handle on the CLI, the scanner will exclude directories that are not relevant to those paths.

Note that for many commands, such as biome check and biome format, the file paths to handle are implicitly set to the current working directory if you do not provide any path explicitly. The targeted scanner also works with such implicit paths, which means that if you run Biome from a subfolder, other folders that are part of the project are automatically exempted.

Use cases where you invoke Biome from the root of the project without providing a path, as well as those where project rules are enabled, are not expected to see performance benefits from this.

Implemented #6234, and fixed #6483 and #6563.
#6488 c5ee385 Thanks @ianzone! - nx.json and project.json have been added to the list of well-known files.
#6720 52e36ae Thanks @minht11! - Added $ symbol to organizeImports :ALIAS: group.

import { action } from '$lib' will be treated as alias import.

Patch Changes

#6712 2649ac6 Thanks @sterliakov! - Fixed #6595: Biome now supports // biome-ignore-all file-level suppressions in files that start with a shebang (#!).
#6758 28dc49e Thanks @arendjr! - Fixed #6573: Grit plugins can now match bare imports.

Example

The following snippet:
```
1
`import $source`
```
will now match:
```
1
import "main.css";
```

#6550 b424f46 Thanks @arendjr! - Type inference is now able to handle logical expressions: &&, ||, and ??.

Examples

1
// We can now infer that because `true` is truthy, the entire expression
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// evaluates to a `Promise`.
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true && Promise.reject("logical operator bypass");
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// And we know that this doesn't:
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false && Promise.reject("logical operator bypass");
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// Truthiness, falsiness, and non-nullishness can all be determined on more
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// complex expressions as well. So the following also works:
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type Nullish = null | undefined;
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type Params = {
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  booleanOption: boolean | Nullish;
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  falsyOption: false | Nullish;
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};
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function foo({ booleanOption, falsyOption }: Params) {
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  // This may be a Promise:
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  booleanOption ?? Promise.reject("logical operator bypass");
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  // But this never is:
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  falsyOption && Promise.reject("logical operator bypass");
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}

#6413 4aa0e50 Thanks @wojtekmaj! - Improved error message in useDateNow rule.
#6673 341e062 Thanks @dyc3! - Fixed a case where the HTML formatter would mangle embedded language tags if whitespaceSensitivity was set to strict
#6642 a991229 Thanks @unvalley! - Fixed #4494: The noSecrets rule now correctly uses the entropyThreshold option to detect secret like strings.
#6520 0c43545 Thanks @arendjr! - Type inference is now able to handle ternary conditions in type aliases.

Note that we don’t attempt to evaluate the condition itself. The resulting type is simply a union of both conditional outcomes.

Example
```
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type MaybeResult<T> = T extends Function ? Promise<string> : undefined;
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// We can now detect this function _might_ return a `Promise`:
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function doStuff<T>(input: T): MaybeResult<T> {
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  /* ... */
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}
```
#6711 1937691 Thanks @sterliakov! - Fixed #6654: Fixed range highlighting of <explanation> placeholder in inline suppression block comments.
#6756 d12b26f Thanks @dyc3! - Fixed #6669: Added an exception to noUnusedImports to allow type augmentation imports.
```
1
import type {} from "@mui/lab/themeAugmentation";
```
#6643 df15ad6 Thanks @skewb1k!
Fixed #4994: LSP server registered some capabilities even when the client did not support dynamic registration.
#6599 5e611fa Thanks @vladimir-ivanov! - Fixed #6380: The noFocusedTests rule now correctly displays the function name in the diagnostic message when a test is focused.

Every instance of a focused test function (like fdescribe, fit, ftest and only) had the word ‘only’ hardcoded. This has been updated to use the actual function name, so the message is now more accurate and specific.

Example for fdescribe:
```
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  i The 'fdescribe' method is often used for debugging or during implementation.
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  i Consider removing 'f' prefix from 'fdescribe' to ensure all tests are executed.
```

#6671 0c9ab43 Thanks @vladimir-ivanov! - Fixed #6634: The useReadonlyClassProperties rule now correctly flags mutations in class getters and in arrow functions within class properties.

Examples:

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class GetterWithMutationValue {
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  #value: string;
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  get value() {
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    if (!this.#value) {
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      this.#value = "defaultValue";
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    }
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    return this.#value;
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  }
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}

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class ClassPropertyArrowFunctionWithMutation {
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  private bar: string | null = null;
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  readonly action = () => {
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    this.bar = "init";
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  };
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}

#6682 ca04cea Thanks @ematipico! - Fixed #6668: Biome Assist is now enabled by default for CSS files.

#6525 66b089c Thanks @arendjr! - Type inference can now infer the return types of functions and methods without annotations.

Examples

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const sneakyObject = {
2
  doSomething() {
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    return Promise.resolve("This is a floating promise!");
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  },
5
};
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// We can now detect that `doSomething()` returns a `Promise`.
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sneakyObject.doSomething();

#6531 c06df79 Thanks @arendjr! - Biome’s type inference now detects the type of properties with getters.

Examples

1
const sneakyObject2 = {
2
  get something() {
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    return new Promise((_, reject) => reject("This is a floating promise!"));
4
  },
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};
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// We now detect this is a Promise:
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sneakyObject2.something;

#6587 a330fcc Thanks @Conaclos! - organizeImports is now able to sort named specifiers and import attributes with bogus nodes.
#6618 6174869 Thanks @Shinyaigeek! - Fixed #6610: JSON import attributes are now correctly detected when they contain extra whitespace.
#6753 fce5d2c Thanks @dyc3! - Improved the error messages when Biome is provided incompatible arguments on the CLI.
#6587 a330fcc Thanks @Conaclos! - Fixed #6491: The action of useSortedKeys removed comments or wrongly transferred them to distinct nodes.
#6696 92964a7 Thanks @unvalley! - Fixed #6633: The noImplicitCoercion rule no longer reports diagnostics for 1 / value expressions.
```
1
1 / value; // no error
```
#6683 43d871e Thanks @ematipico! - Fixed #6537: Biome no longer removes the trailing comma from JSON files when formatter.json.trailingCommas is explicitly set to "all".
#6693 bfdce0b Thanks @dyc3! - Fixed #6691: The HTML parser will now consider . to be a valid character for tag names.
#6716 ead03d1 Thanks @siketyan! - The Biome LSP server no longer responds with an error for a textDocument/codeActions request when Biome doesn’t support a feature for the file (e.g. Code actions aren’t supported in GritQL files).
#6679 7bf9a60 Thanks @marko-hologram! - Fixed #6638: JavaScript formatter overrides options now correctly override expand option. JSON formatter overrides options now correctly override bracketSpacing and expand options.
#6717 7f5b541 Thanks @siketyan! - Fixed #6688: the noUselessFragments no longer reports <Fragment /> elements that includes HTML character entities.
#6600 853e1b5 Thanks @daivinhtran! - Fixed #4677: The noUnusedImports rule won’t produce diagnostics for types used in comments of static members anymore.
#6662 3afc804 Thanks @arendjr! - If a nested configuration file is ignored by the root configuration, it will now actually be ignored.

Biome has an exception in place for configuration files so they cannot be ignored, because the configuration files are vital to Biome itself. But this exception was incorrectly applied to nested configurations as well. Now only the root configuration is exempt from being ignored.
#6596 c0718ca Thanks @ematipico! - Fixed #6566: Biome no longer errors when using the option --files-ignore-unknown=true in stdin mode.

Biome has also become less strict when using --stdin-file-path in stdin mode. It will no longer error if the file path doesn’t contain an extension, but instead it will return the original content.
#6562 153eda7 Thanks @vladimir-ivanov! - Added the nursery rule noMagicNumbers. The rule detects and reports the use of “magic numbers” — numeric literals that are used directly in code without being assigned to a named constant.

Example
```
1
let total = price * 1.23; // Magic number for tax rate will highlight 1.23 as magic number
```
#6663 af78d6d Thanks @ematipico! - Fixed #6656: Biome now correctly formats HTML void elements such as <meta> when they contain a self-closing slash.
```
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<meta foo="bar" />
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<meta foo="bar">
```
#6732 31e4396 Thanks @vladimir-ivanov! - Resolved #6281: Improved performance of handling package.json files in the scanner.
#6625 19cb475 Thanks @arendjr! - Fixed #6616: Fixed an issue with extending configurations that contained an explicit root field while the configuration in the project did not.
#6650 19aab18 Thanks @sterliakov! - Fixed #6621: Improved handling of multiple adjacent line suppressions. Biome now handles such suppressions separately, tracking whether each one is used.
#6700 cdd6e17 Thanks @denbezrukov! - Fixed #6680: Biome incorrectly formatted container-style queries by inserting misplaced spaces.
```
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@container style (--responsive: true) {}
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@container style(--responsive: true) {}
```
#6709 ecf3954 Thanks @dyc3! - Fixed #6038: Fixed a false positive in noShadow where a function parameter in a type definition was erroneously flagged as a violation.

#6593 a4acbb7 Thanks @arendjr! - Type inference is now able to handle ternary conditions in expressions.

Examples

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const condition = Math.random() > -1; // Always true, but dynamic to linter
2

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// We now detect that this may return a `Promise`.
4
condition ? Promise.reject("ternary bypass") : null;
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// On the other hand, we know the following is never a `Promise`:
7
const alwaysFalsy = 0;
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alwaysFalsy ? Promise.reject("ternary bypass") : null;

#6428 4b501d3 Thanks @siketyan! - Added MemoryFileSystem to the WASM API.

You can now insert a file from your JS code:

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import { MemoryFileSystem, Workspace } from "@biomejs/wasm-web";
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const fs = new MemoryFileSystem();
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const workspace = Workspace.withFileSystem(fs);
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fs.insert("/index.js", new TextEncoder().encode("let foo = 1;"));
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fs.remove("/index.js");

#6594 626d4a1 Thanks @ematipico! - Fixed #6528: Biome didn’t return the correct output when applying source.fixAll.biome inside Astro/Vue/Svelte files that contained safe fixed.