Default Rules and Risk Guide

This guide describes the current configuration model, major rules, and auto-fix risks. Source comments explain current intent; historical differences belong in CHANGELOG.md.

Policy

Rules are selected in this order:

1. Follow common JavaScript, TypeScript, and Vue conventions while keeping code concise and readable.
2. Detect real bugs and type-safety problems.
3. Preserve cross-project consistency.
4. Apply Fast project style preferences last.

Rules that only satisfy ESLint by changing valid semantics, adding boilerplate, or forcing uncommon forms do not belong in the defaults.

Configuration model

Vue 3 and UniApp are separate named complete configurations from the root entry:

• vueConfig handles plain Vue projects only.
• uniAppConfig adds .nvue, UniApp globals, manifest behavior, and the unpackage ignore.

The root entry has no default export. It exposes vueConfig, uniAppConfig, createVueProjectConfigs(), createUniAppProjectConfigs(), createBaseConfigs(), defineRules(), and their types.

SDKs, Node.js, and other framework-neutral projects use createBaseConfigs(). React, Angular, Markdown, and Lodash compose explicitly from ./configs; manifest sorting is part of every complete configuration.

Preset sources

Domain	Preset or implementation
JavaScript	@eslint/js recommended plus local high-confidence rules
TypeScript	typescript-eslint recommendedTypeChecked plus Project Service
Vue	eslint-plugin-vue flat/recommended plus type-aware TypeScript
React	@eslint-react recommended/type-checked plus React Hooks Flat Recommended
Angular	Angular ESLint TypeScript, template, and accessibility recommended presets
JSON	eslint-plugin-jsonc recommended presets for three dialects
Import	eslint-plugin-import-x recommended plus a general ordering warning
RegExp	Explicit correctness, safety, and super-linear backtracking rules
Prettier	eslint-config-prettier conflict disabling

The complete strictTypeChecked, stylisticTypeChecked, and mechanical all presets are not enabled. Extra rules are limited to low-false-positive checks that directly improve correctness or readability.

JavaScript and Import

• camelcase: ["error", { properties: "never" }] applies to variables and types while external protocol properties retain their original names.
• no-empty permits a completely empty catch and reports other empty blocks.
• no-void is an error; void is not used to hide a Promise or express an ignored return value.
• Real-risk rules such as no-eval, no-implied-eval, no-new-func, no-promise-executor-return, and no-debugger are errors.
• curly requires consistent braces only for multiline branches and does not force braces on every single-line branch.
• import-x/first and import-x/no-duplicates are errors.
• import-x/order is an error and fixes declaration order; common framework, tool, and @/** path groups extend the general groups.
• pathGroupsExcludedImportTypes: ["type"] keeps type imports in the final type group.
• Non-style side-effect imports participate in ordering. style-imports-last requires a final contiguous stylesheet group without sorting within it, preserving CSS cascade order.
• sort-imports is an error and only normalizes members inside one import declaration; prefer-object-has-own is not enabled.

TypeScript

TypeScript always uses Project Service and recommendedTypeChecked. Linted files must belong to a discoverable tsconfig.json.

• .ts, .mts, and .cts files are SDK-like module boundaries: explicit-module-boundary-types is an error, so exported functions and public boundaries of exported classes require explicit types.
• .tsx files are UI component files: type-aware correctness rules remain enabled, but module-boundary annotations are not required for inferable JSX return types.
• explicit-function-return-type is disabled, leaving internal functions, local handlers, and callbacks to TypeScript inference.
• no-inferrable-types preserves explicit parameter and property types and only removes annotations without contract value, such as obvious local-variable types.
• Vue/NVue SFCs and standalone TSX components disable module-boundary and function-return requirements to preserve common concise component forms.
• no-floating-promises is disabled because waiting, returning, or handling a Promise depends on business semantics.
• require-await is an error; an async function without await changes return and exception semantics and should lose async.
• no-misused-promises, await-thenable, unsafe-type rules, exhaustive switches, getter/setter compatibility, and other high-confidence checks are errors.
• return-await requires await only when needed for correct error handling.
• Standard non-null assertions are permitted, while contradictory optional-chain or nullish-coalescing combinations remain errors.
• no-explicit-any and no-deprecated warn.
• no-unnecessary-condition, unified-signatures, and syntax-only preferences are disabled to preserve runtime guards and public overloads.
• Template strings allow numbers and booleans; dynamic property deletion and static utility classes are not forcibly rewritten.
• prefer-nullish-coalescing does not force primitive values from || to ??; prefer-optional-chain applies only when the type explicitly contains null or undefined.

Vue

• The official flat/recommended preset is the general Vue baseline.
• no-v-html warns so XSS risk is visible while sanitized content remains possible.
• require-explicit-emits, no-dupe-keys, no-mutating-props, no-setup-props-reactivity-loss, no-ref-object-reactivity-loss, and no-reserved-component-names are errors for Vue SFC and Vue JSX/TSX component scripts.
• attribute-hyphenation, no-v-text-v-html-on-component, and attributes-order remain limited to .vue/.nvue templates; attributes-order sorts definition, list-rendering, conditional, render-modifier, unique, global, ordinary, event, and content attributes.
• JSX attributes retain JavaScript camelCase conventions and do not inherit the template kebab-case rule.
• Setup props/ref reactivity loss and invalid custom-event names remain errors.

UniApp boundary

Only the UniApp entry declares uni, uniCloud, page APIs, and conditional-platform objects such as wx, plus, my, and tt. The plain Vue entry neither receives these globals nor ignores unpackage.

ESLint does not execute conditional compilation. It can avoid no-undef inside platform branches but cannot prove that an object occurs under the correct #ifdef.

Manifest sorting and auto-fix

package.json and tsconfig*.json sorting is enabled by default in createBaseConfigs(), vueConfig, and uniAppConfig. The individual factories remain available for custom composition.

Review these fixes carefully:

• Import groups, path groups, type-import placement, and non-style side-effect import order.
• Stylesheet imports are only checked for final placement and are not moved or reordered automatically.
• Separate TypeScript import type and export type declarations.
• Default manifest key ordering.

Check before fixing:

pnpm exec eslint .
pnpm exec eslint . --fix

Maintenance policy

1. Inspect effective rules after recommended preset upgrades so upstream changes do not silently alter severity.
2. Every new rule must explain the real problem it catches, its false-positive boundary, and whether it auto-fixes.
3. Frameworks add parsers, file scopes, and framework semantics without creating another language strictness tier.
4. Public entries, parser scopes, or auto-fix changes require matching type, runtime, and package tests.