js-google

# Google JavaScript Best Practices Comprehensive JavaScript style and best practices guide based on Google's official JavaScript Style Guide, designed for AI agents and LLMs. Contains 47 rules across 8 categories, prioritized by impact to guide automated refactoring and code generation. ## When to Apply Reference these guidelines when: - Writing new JavaScript or ES6+ code - Structuring modules and managing imports/exports - Adding JSDoc type annotations and documentation - Reviewing code for naming and style consistency - Refactoring existing JavaScript code ## Rule Categories by Priority | Priority | Category | Impact | Prefix | |----------|----------|--------|--------| | 1 | Module System & Imports | CRITICAL | `module-` | | 2 | Language Features | CRITICAL | `lang-` | | 3 | Type Safety & JSDoc | HIGH | `type-` | | 4 | Naming Conventions | HIGH | `naming-` | | 5 | Control Flow & Error Handling | MEDIUM-HIGH | `control-` | | 6 | Functions & Parameters | MEDIUM | `func-` | | 7 | Objects & Arrays | MEDIUM | `data-` | | 8 | Formatting & Style | LOW | `format-` | ## Quick Reference ### 1. Module System & Imports (CRITICAL) - [`module-avoid-circular-dependencies`](references/module-avoid-circular-dependencies.md) - Prevent loading failures from circular imports - [`module-file-extension-in-imports`](references/module-file-extension-in-imports.md) - Include .js extension in import paths - [`module-named-exports-over-default`](references/module-named-exports-over-default.md) - Prefer named exports for consistency - [`module-no-duplicate-imports`](references/module-no-duplicate-imports.md) - Import from same file only once - [`module-no-import-aliasing`](references/module-no-import-aliasing.md) - Keep original export names - [`module-source-file-structure`](references/module-source-file-structure.md) - Follow standard file structure order ### 2. Language Features (CRITICAL) - [`lang-const-over-let-over-var`](references/lang-const-over-let-over-var.md) - Use const by default, never var - [`lang-es6-classes-over-prototypes`](references/lang-es6-classes-over-prototypes.md) - Use class syntax over prototype manipulation - [`lang-explicit-semicolons`](references/lang-explicit-semicolons.md) - Always use explicit semicolons - [`lang-no-eval`](references/lang-no-eval.md) - Never use eval or Function constructor - [`lang-no-modify-builtins`](references/lang-no-modify-builtins.md) - Never modify built-in prototypes - [`lang-no-non-standard-features`](references/lang-no-non-standard-features.md) - Use only standard ECMAScript features - [`lang-no-primitive-wrappers`](references/lang-no-primitive-wrappers.md) - Never use primitive wrapper objects - [`lang-no-with-statement`](references/lang-no-with-statement.md) - Never use the with statement ### 3. Type Safety & JSDoc (HIGH) - [`type-cast-with-parentheses`](references/type-cast-with-parentheses.md) - Use parentheses for type casts - [`type-enum-annotations`](references/type-enum-annotations.md) - Annotate enums with static literal values - [`type-explicit-nullability`](references/type-explicit-nullability.md) - Use explicit nullability modifiers - [`type-jsdoc-required-for-exports`](references/type-jsdoc-required-for-exports.md) - Require JSDoc for exported functions - [`type-template-parameters`](references/type-template-parameters.md) - Always specify template parameters - [`type-typedef-for-complex-types`](references/type-typedef-for-complex-types.md) - Use typedef for complex object types ### 4. Naming Conventions (HIGH) - [`naming-constant-case-for-constants`](references/naming-constant-case-for-constants.md) - Use CONSTANT_CASE for immutable values - [`naming-descriptive-over-brief`](references/naming-descriptive-over-brief.md) - Prefer descriptive names over brevity - [`naming-file-naming-conventions`](references/naming-file-naming-conventions.md) - Use lowercase with dashes or underscores - [`naming-lowercamelcase-for-methods`](references/naming-lowercamelcase-for-methods.md) - Use lowerCamelCase for methods and variables - [`naming-no-dollar-prefix`](references/naming-no-dollar-prefix.md) - Avoid dollar sign prefix in identifiers - [`naming-uppercamelcase-for-classes`](references/naming-uppercamelcase-for-classes.md) - Use UpperCamelCase for classes ### 5. Control Flow & Error Handling (MEDIUM-HIGH) - [`control-comment-empty-catch`](references/control-comment-empty-catch.md) - Document empty catch blocks - [`control-for-of-over-for-in`](references/control-for-of-over-for-in.md) - Prefer for-of over for-in - [`control-strict-equality`](references/control-strict-equality.md) - Use strict equality except for null checks - [`control-switch-default-last`](references/control-switch-default-last.md) - Always include default case in switch - [`control-throw-error-objects`](references/control-throw-error-objects.md) - Always throw Error objects ### 6. Functions & Parameters (MEDIUM) - [`func-arrow-functions-for-nested`](references/func-arrow-functions-for-nested.md) - Prefer arrow functions for nested functions - [`func-arrow-parentheses`](references/func-arrow-parentheses.md) - Always use parentheses around arrow params - [`func-default-parameters`](references/func-default-parameters.md) - Use default parameters instead of conditionals - [`func-rest-parameters-over-arguments`](references/func-rest-parameters-over-arguments.md) - Use rest parameters over arguments - [`func-spread-over-apply`](references/func-spread-over-apply.md) - Use spread operator instead of apply ### 7. Objects & Arrays (MEDIUM) - [`data-array-literals-over-constructor`](references/data-array-literals-over-constructor.md) - Use array literals over Array constructor - [`data-destructuring-for-multiple-values`](references/data-destructuring-for-multiple-values.md) - Use destructuring for multiple properties - [`data-no-mixing-quoted-unquoted-keys`](references/data-no-mixing-quoted-unquoted-keys.md) - Never mix quoted and unquoted keys - [`data-object-literals-over-constructor`](references/data-object-literals-over-constructor.md) - Use object literals over constructor - [`data-spread-over-concat-slice`](references/data-spread-over-concat-slice.md) - Use spread over concat and slice - [`data-trailing-commas`](references/data-trailing-commas.md) - Use trailing commas in multi-line literals ### 8. Formatting & Style (LOW) - [`format-braces-required`](references/format-braces-required.md) - Always use braces for control structures - [`format-column-limit`](references/format-column-limit.md) - Limit lines to 80 characters - [`format-one-statement-per-line`](references/format-one-statement-per-line.md) - Place one statement per line - [`format-single-quotes`](references/format-single-quotes.md) - Use single quotes for string literals - [`format-two-space-indent`](references/format-two-space-indent.md) - Use two-space indentation ## How to Use Read individual reference files for detailed explanations and code examples: - [Section definitions](references/_sections.md) - Category structure and impact levels - [Rule template](assets/templates/_template.md) - Template for adding new rules ## Full Compiled Document For a complete compiled guide with all rules, see [AGENTS.md](AGENTS.md). ## Reference Files | File | Description | |------|-------------| | [AGENTS.md](AGENTS.md) | Complete compiled guide with all rules | | [references/_sections.md](references/_sections.md) | Category definitions and ordering | | [assets/templates/_template.md](assets/templates/_template.md) | Template for new rules | | [metadata.json](metadata.json) | Version and reference information |