jsdoc

JSDoc

The detailed JSDoc format guide with examples for every case. The always-on essentials live in the jsdoc rule. Reach here when you need the full reference.

@example format

Short one-liner: label on the @example line, code as inline backtick on the next line

/**
 * @example Required parameter
 * `name: Type`
 *
 * @example Optional parameter
 * `name?: Type`
 */

Multi-line: fenced code block immediately after @example

/**
 * @example
 * ```ts
 * const result = buildParams(node, {
 *   paramsType: 'inline',
 * })
 * ```
 */

Multiple variants: use multiple @example blocks

/**
 * @example Object mode
 * `{ id, data, params }: { id: string; data: Data; params?: QueryParams }`
 *
 * @example Inline mode
 * `id: string, data: Data, params?: QueryParams`
 */

Rules

Rule	Correct	Incorrect
Label + inline code	@example Required\n\name: Type``	@example \name: Type`` (code on tag line)
Multi-line code	Fenced ```ts ``` block	Bare code lines without a fence
Short examples	Inline backtick	Triple-backtick fence (too heavy)
One concern per example	Separate @example blocks	One example covering all cases

Tags

Use frequently

Tag	Purpose	Notes
@default	Default value	Only when the default is non-obvious (omit for undefined)
@example	Usage example	Prefer for complex or multi-variant APIs
@note	Important caveat	Version info, breaking changes
@deprecated	Mark as deprecated	Include a migration path

Use sparingly

Tag	Purpose
@see	Reference external docs
@internal	Internal API
@beta	Experimental

Avoid (TypeScript already provides these)

• @param: use TypeScript parameter types
• @returns: use the TypeScript return type
• @type: use a TypeScript type annotation
• @typedef: use type or interface
• @default undefined: optional (?) already implies this

Documentation patterns

Simple property: always multi-line

/**
 * Output directory for generated files.
 */
outDir?: string

Never use single-line /** description */. Always expand to multi-line.

Property with a non-obvious default

/**
 * Maximum number of concurrent callbacks during traversal.
 * Higher values overlap I/O-bound work; lower values reduce memory pressure.
 *
 * @default 30
 */
concurrency?: number

Do not add @default false or @default undefined when the TypeScript type already makes the default obvious.

Enum or union with options

/**
 * How path parameters are emitted in the function signature.
 * - `'object'` groups them as a single destructured parameter
 * - `'inline'` spreads them as individual parameters
 * - `'inlineSpread'` emits a single rest parameter
 */
pathParamsType: 'object' | 'inline' | 'inlineSpread'

Nested properties: every field gets its own multi-line JSDoc

names?: {
  /**
   * Name for the request body parameter.
   * @default 'data'
   */
  data?: string
  /**
   * Name for the query parameters group parameter.
   * @default 'params'
   */
  params?: string
}

Function documentation

Only add JSDoc when it adds value beyond the signature:

// No JSDoc needed: the signature is self-explanatory
function camelCase(str: string): string { ... }

// JSDoc adds value: it explains behavior and non-obvious edge cases
/**
 * Returns `true` when the schema resolves to a plain string output.
 *
 * - `string`, `uuid`, `email`, `url`, `datetime` are always plain strings.
 * - `date` and `time` are plain strings when their `representation` is `'string'`.
 */
function isStringType(node: SchemaNode): boolean { ... }

Guidelines

Do:

• Document what the property does, not its TypeScript type
• Give every exported type, property, and function a JSDoc comment
• Always use multi-line JSDoc blocks
• Use concrete, full-sentence descriptions
• Include @default only when the default is non-obvious
• Use multiple @example blocks for different variants
• Keep @example labels short and descriptive

Do not:

• Write single-line /** description */
• Write @default undefined
• Put code directly on the @example line
• Use @param or @returns tags
• Over-document trivial, self-explanatory properties

Tag order

1. Description (required)
2. Bullet list of variants or behaviors (if applicable)
3. @default (if non-obvious)
4. @example (one or more)
5. @note (if needed)
6. @deprecated (if applicable)
7. @see (if providing references)