ts-code-conventions

name

ts-code-conventions

description

ACTIVATE whenever writing or modifying TypeScript code in src/. ACTIVATE for code review, formatting, or 'coding standards'. Provides TS-specific code style examples for the cross-language rules defined in craft:code-style-principles, plus TS-specific patterns (optional chaining, nullish coalescing, template literals, no truthy/falsy). DO NOT use for: TypeScript typing rules (see ts-conventions), test conventions. Use when this capability is needed.

Code Conventions — TypeScript

The cross-language rules (control-structure spacing, early return, continue vs if/else, parameter ordering, flatten null checks) are defined in craft:code-style-principles. This skill keeps TS-specific syntax (optional chaining, nullish coalescing, template literals) and pointers to the project's references/code-examples.md.

See also: ts-conventions for typing rules (strict mode, branded types).

These conventions go beyond standard linting rules (eslint/prettier).

For complete worked examples (control-structure spacing, early return, continue patterns, parameter ordering), read references/code-examples.md.

TS-specific: Optional Chaining and Nullish Coalescing

Use ?. to flatten nested null checks, and ?? for "default if null/undefined".

// Optional chaining
if (customer.personalInfo?.usPerson === true) {
  types.push('us_person');
}

// Nullish coalescing
const name = user.displayName ?? 'Anonymous';

TS-specific: No Implicit Truthy / Falsy

Use explicit comparisons instead of relying on JavaScript's truthy/falsy coercion.

// ✅ Explicit checks
if (array.length > 0) { /* ... */ }
if (string === '') { /* ... */ }
if (value !== null && value !== undefined) { /* ... */ }

// ✅ Exception — booleans can be checked directly
if (isValid) { /* ... */ }

TS-specific: Template Literals Over Concatenation

const message = `Hello ${user.name}, you have ${count} items`;

Quick Reference (TS-specific only)

For the cross-language quick reference (early return, continue, blank lines, parameter ordering), see craft:code-style-principles.

Rule	Example
Optional chaining	a?.b?.c instead of nested if
Nullish coalescing	value ?? 'default'
Explicit checks	array.length > 0 (not array.length)
Template literals	`Hello ${name}` (not 'Hello ' + name)

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Source: FabienSalles/claude-marketplace — distributed by TomeVault.