| name | javascript-language |
| description | Modern JavaScript (ES2022+) patterns for clean, maintainable code. Use when working with modern JavaScript features like optional chaining, nullish coalescing, or ESM. |
| metadata | {"triggers":{"files":["**/*.js","**/*.mjs","**/*.cjs"],"keywords":["const","let","arrow","async","await","promise","destructuring","spread","class"]}} |
JavaScript Language Patterns
Priority: P0 (CRITICAL)
Implementation Guidelines
- Variables: const default. let if needed. No var — block scope only.
- Functionality: Use
Arrow Functions for callbacks/inlines; Function Declaration for core logic.
- Async Logic: Use async/await with try/catch and Promise.all() for parallel operations. ESM import/export only. No Callbacks — promisify everything.
- Modern Syntax: Use Destructuring, Spread (...), Optional Chain ?. and Nullish ?? coalescing.
- String Handling: Use
Template Literals (backticks) for interpolation and multi-line strings.
- Data Collections: Prefer
map, filter, and reduce over imperative for loops.
- Modules: Standardize on ESM import/export; use Named Exports over Default.
- Encapsulation: Leverage
#private class fields for encapsulation.
- Error States: Throw
new Error() with descriptive messages; never throw strings.
Anti-Patterns
- No var — Block scope only.
- No
==: Strict ===.
- No
new Object(): Use literals {}.
- No Callbacks: Promisify everything.
- No Mutation: Immutability first.
Code & Reference
See references/REFERENCE.md for modern syntax, async patterns, private fields, and functional programming examples.
Related Topics
best-practices | tooling
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