performant

A variant of recommended for projects where performance is a priority and some lint rules get in the way.

Usage

{
  "extends": ["@repobuddy/biome/performant"]
}

Options

None. The config takes no parameters.

Effective config

This is the content of packages/biome/performant.jsonc.

{
  "files": {
    "includes": ["**", "!**/.vscode/**/*.txt", "!**/*.md"]
  },
  "formatter": {
    "enabled": true,
    "indentStyle": "tab",
    "lineEnding": "lf",
    "lineWidth": 120
  },
  "javascript": {
    "formatter": {
      "quoteStyle": "single",
      "semicolons": "asNeeded",
      "trailingCommas": "none"
    }
  },
  "linter": {
    "enabled": true,
    "rules": {
      "recommended": true,
      "complexity": {
        "noForEach": "off",
        "useLiteralKeys": "off",
        "noCommaOperator": "off"
      },
      "correctness": {
        "noInnerDeclarations": "warn",
        "noUnusedVariables": { "level": "error", "options": { "ignoreRestSiblings": true } },
        "useExhaustiveDependencies": "off"
      },
      "style": {
        "noNonNullAssertion": "off",
        "noParameterAssign": "off",
        "useTemplate": "off",
        "useAsConstAssertion": "error",
        "useDefaultParameterLast": "error",
        "useEnumInitializers": "error",
        "useSelfClosingElements": "error",
        "useSingleVarDeclarator": "error",
        "noUnusedTemplateLiteral": "error",
        "useNumberNamespace": "error",
        "noInferrableTypes": "error",
        "noUselessElse": "error",
        "useNodejsImportProtocol": "error"
      },
      "suspicious": {
        "noAssignInExpressions": "off",
        "noExplicitAny": "off",
        "noVar": "off"
      }
    }
  },
  "assist": { "actions": { "source": { "organizeImports": "off" } } },
  "overrides": [
    {
      "includes": ["**/package.json"],
      "formatter": { "lineWidth": 20 }
    }
  ]
}

Files

Identical to recommended: **, minus **/.vscode/**/*.txt and **/*.md.

Formatter

Same as recommended (tabs, lf, width 120, single quotes, semicolons as needed, package.json width 20), with one change: javascript.formatter.trailingCommas is none.

Linter

linter.enabled and recommended are true. The rules below are the same as in recommended, with the same levels and options: noForEach, useLiteralKeys, noCommaOperator, noUnusedVariables, useExhaustiveDependencies, noNonNullAssertion, noParameterAssign, useTemplate, useAsConstAssertion, useDefaultParameterLast, useEnumInitializers, useSelfClosingElements, useSingleVarDeclarator, noUnusedTemplateLiteral, useNumberNamespace, noInferrableTypes, noUselessElse, useNodejsImportProtocol, noAssignInExpressions, and noExplicitAny. See recommended for what each rule flags.

The rules that differ from recommended:

Rule	Level in `performant`	Biome default (2.5.15)	Effect
`correctness/noInnerDeclarations`	warn	error	Reports `var` and function declarations in nested blocks as warnings.
`correctness/noUnusedImports`	not set	warn	Reports unused imports as warnings, not errors.
`suspicious/noVar`	off	not reported	`var` is accepted.
`suspicious/noConsole`	not set	not reported	`console.log()` is accepted.

Assist

Action	Value
`assist.actions.source.organizeImports`	`off`

Overrides

`includes`	Effect
`**/package.json`	`formatter.lineWidth` is `20`

There is no JSON parser override, so comments and trailing commas in tsconfig*.json and .vscode/**/*.json follow Biome’s own parsing.

Examples

Each fixture under packages/biome/tests/performant exercises one rule.

Flagged at error:

// style/useNodejsImportProtocol
import { deepEqual } from 'assert'

Flagged at warn:

// correctness/noInnerDeclarations
export function noInnerDeclarations(): string {
  const greeting = 'Hello World!'
  if (greeting) {
    var c = greeting[0]
    return c!
  }
  return greeting
}

Accepted because the rule is off:

// suspicious/noVar
export function hello(): string {
  var greeting = 'Hello World!'
  return greeting
}

// complexity/noForEach
;[].forEach((x) => void console.info(x))

// style/useTemplate
export const s = foo + 'b'