LaunchCodeNotes

JSDoc and Semver

:construction: UNDER CONSTRUCTION: This document is a work in progress, however unlike most of the documents under construction, this one is actually usable enough for the moment.

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Introduction

Installation

I recommend installing JSDoc from NPM.

To install the latest version of JSDoc globally (which may require sudo):

npm install -g jsdoc

To install the latest version of JSDoc locally and save it in your package’s package.json file:

npm install --save-dev jsdoc

There’s also another tool called jsdoc-to-markdown that can generate API documentation from a JavaScript file that is using JSDoc, but I’m not goin to get into that right now.

Tags

JSDoc supports two kinds of tags:

• Block tags which are top level of a JSDoc Comment.
  • Block tags usually provide detailed information about your code, such as the parameters that a function accepts.
  • Block tags always begin with an at sign (@). Each block tag mus be followed by a line break, with the exception of the last block tag in a JSDoc comment.
• Inline tags which are within the text of a block tag or a description.
  • Inline tags usually link to other parts of the documentation, similar to the anchor tag (<a>) in HTML.
  • Inline tags also begin with an at sign, however inline tags and their text must be included in curly braces. If your tag’s text includes a closing curly brace (}), you must escape ith with a leading backslas (\). You do not need to use a line break after inline tags.

Most JSDoc tags are block tags.

Examples

In the following examples, @param is a block tag, and {@link} is an inline tag.

You can use inline tags with a description (like in the first example below), or within a block tag (like in the second example below).

When you use multiple block tags in a JSDoc comment, they must be separated by line breaks.

Block and inline tags in JSDoc comments

/**
 * Set the shoe's color. Use {@link Shoe#setSize} to set the shoe size.
 *
 * @param {string} color - The shoe's color.
 */
Shoe.prototype.setColor = function(color) { /* ... */ };

Inline tag used within a block tag

/**
 * Set the shoe's color. Use {@link Shoe#setSize} to set the shoe size.
 *
 * @param {SHOE_COLORS} color - The shoe's color. Must be an enumerated
 * value of {@link SHOE_COLORS}
 */
Shoe.prototype.setColor = function(color) { /* ... */ };

Multiple block tags separated by line breaks

/**
 * Set the color and type of the shoelaces.
 *
 * @param {LACE_COLORS} color - The shoelace color.
 * @param {LACE_TYPES} type - The type of shoelace.
 */
Shoe.prototype.setLaceType = function(color, type) { /* ... */ };

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Block Tags

@abstract

synonms: @virtual

This member must be implemented (or overridden) by the inheritor.

@access

Specifies the access level of this member (private, package-private, public, or protected).

@alias

Treat a member as if it had a different name.

@arg

See @param

@argument

See @param

@async

Indicate that a function is asynchronous.

@augments

See @extends

@author

Identify the author of an item.

@borrows

This object uses something from another object.

@callback

Document a callback function.

@class

synonyms: @constructor

This function is intended to be called with the new keyword.

See also

• @hideconstructor (in the @constructor context)
• @interface (in the @class context)
• @extends for class inheritance.
• @implements for interface implementation.

@classdesc

Use the following text to describe the entire class.

@const

synonyms: @constant

Document an object as a constant (const).

@constant

See @const

@constructor

See @class

@constructs

This function member will be the constructor for the previous class.

@copyright

Documents some copyright information.

@default

synonyms: @defaultvalue

==Documents the default value.==

@defaultvalue

See @default

@depricated

Documents that something is no longer the preferred way. (When you use this, provide an alternative whenever possible)

@desc

synonyms: @description

Describe a symbol.

See also @summary

@description

See @desc

@emits

See @fires

@enum

Describe a collection of related properties. Typically, in UML, this collection would be part of an object with the enumeration stereotype.

classDiagram
class Access {
<<enumeration>>
package
private
protected
public
}

@event

Document an event.

@example

Provide an example of how to use a documented item.

@exception

See @throws

@exports

Identify the member that is exported by a JavaScript module.

@external

synonyms: @host

Identifies an external class, namespace, or module.

:reminder_ribbon: TODO: Is @external the proper syntax for #include, import, or require?

@extends

synonyms: @augments

Indicates that a symbol inherits from, and adds to, a parent symbol.

See also

• class
• implements

@file

synonyms: @fileoverview, @overview

Describe a file. Typically, I just use it to say what the file’s name is.

@fileoverview

See @file

@fires

synonyms: @emits

Describe the events this method may fire.

@func

synonyms: @function, @method

Describe a function or method.

See also

• @param

• @property

• @var

@function

See @func

@generator

Indicate that a function is a generator function.

See also @yields

@global

Document a global object.

@hideconstructor

Indicate that the constructor should not be displayed.

See also @constructor

@host

See @external

@ignore

Omit a symbol from the documentation.

@implements

This symbol implments an interface.

See also

• @extends
• @interface

@inheritdoc

Indicate that a symbole should inherit its parent’s documentation.

@inner

Document an inner object.

@instance

Document an instance member.

See also @static

@interface

This symbol is an interface that others can implement.

See also

• @class
• @implements

@kind

What kind of symbol is this?

:reminder_ribbon: TODO: Doesn’t UML have a defintion of “kind”?

@lends

Document properties on an object literal as if they belong to a symbol with a given name.

@license

Identify the license that applies to this code.

:reminder_ribbon: TODO: List some common options.

@listens

Lit the events that a symbol listens for.

See also @event.

@member

See @var

@method

See @func

@memberof

This symbol belongs to the parent symbol.

:reminder_ribbon: TODO: Could this be related to @namespace?

@mixes

This object mixes in all the members from another object.

@mixin

Documents a @mixin object. (More common in Ruby than JavaScript.)

@module

Document a JavaScript module.

@name

Document a the name of an object.

@namespace

Document a namespace object.

@override

Indicates that a symbol overrides its parent.

@overview

See @file

@package

This symbol is menat to be package-private.

:information_source:: In Java, this symbol indicates a package name.

See also

• @access
• @public
• @protected
• @private

@param

synonyms: @arg, @argument

Dcoumetn the parameter to a function.

See also @function

@private

This symbol is meant to be `private.

See also:

• @access
• @package
• @public
• @protected

@prop

See @property

@property

Document a property of an object.

@protected

This symbol is meant to be protected.

See also:

• @access
• @package
• @public
• @private

@public

This symbol is meant to be public.

See also:

• @access
• @package
• @private
• @protected

@readonly

This symbol is meant to be read-only.

See also: @const

@requires

This file requires a Javascript module.

@return

See @returns

@returns

synonyms: @return

Document the return value of a function.

@see

Refer to some other documentation for more information.

@since

When was this feature added. (Use semantic versioning!)

See also @version

@static

Document a static member.

See also:

• @instance
• @member

@summary

A shorter version of the full description.

See also @desc

@this

What does the this keyword refer to here?

@throws

synonym: @exception

Describe what errors could be thrown.

@todo

Document task to be completed.

@tutorial

Insert a link to ain included tutorial file.

@type

Document the type of an object

@typedef

Document a custom type.

@variation

Distinguish different objects with the same name.

@version

Document the version number of an item. (Use semantic versioning!)

:reminder_ribbon: TODO: Say something about semver.

See also @since

@var

synonyms: @member

Documents a member.

See also

• @func
• @member
• @instance
• @static

@virtual

See @abstract

@yield

See @yields

@yield

Document the vaule yielded by a generator function.

See also:

• @generator
• @returns

Inline Tags

{@link}

synonyms: {@linkcode}, {@linkplain}

Link to another item in the documentation.

{@linkcode}

See {@link}

{@linkplain}

See {@link}

{@tutorial}

Link to a tutorial.

See also @tutorial

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Versioning

Just about any project now-a-days uses what is caled semantic versioning to list what version of their project is (@version) and since when specific functions were part of a project (@since).

The quick rundown is that the numbers for the version are made of three parts.

Given a version number MAJOR.MINOR.PATCH, increment the:

1. MAJOR version when you make incompatible API changes
2. MINOR version when you add functionality in a backwards compatible mannor.
3. PATCH version when you make backwards compatible bug fixes.

Additional labels for pre-release and build metadata are available as extension to the MAJOR.MINOR.PATCH format.

Semantic Versioning Specfications (Semver)

1. Software using SemVer MUST declare a public API. This API could be declared in the code itself on exist stricly in documentation. However it is done, it SHOULD be precise and comprehensive.
2. A normal version number MUST take the form X.Y.Z where X, Y, and Z are non-negative integers, and MUST NOT contain leading zeros. X is the major version, Y is the minor version, and Z is the patch version. Each elements must increase numerically. (e.g. 1.9.0 → 1.10.0 → 1.11.0)
3. Once a version package has been released, the contents of that version MUST NOT be modified. Any modifications MUST be released as a new version.
4. Major version zero (0.Y.Z) is for initial development. Anything MAY cange at the time. The Public API SHOULD NOT be considered stable.
5. Version 1.0.0 defines the public API. The way in which the version number is incremented after the release is dependent on this public API and how it changes.
6. Patch version Z (x.y.Z | x > 0) MUST be incremented if only backward compatible bug fixes are introduced. A bug fix is defined as an internal change that fixes incorrect behavior.
7. Minor version Y (x.Y.z | x > 0) MUST be incremented if new, backwards compatible functionality is introduced to the public API. It MUST be incremented if any public API functionality is marked as deprecated. It MAY be incremented if substantial new functionality or improvements are introduced within the private code. It MAY include patch level changes. Patch version MUST be reset to 0 when minor version is incremented.
8. Major version X (X.y.z | X > 0) MUST be incremented if any backwards incompatible changes are introduced to the public API. It MAY also include minor and patch level changes. Patch and minor version MUST be reset to 0 when major version in incremented.
9. A pre-release version MAY be denoted by appending a hypen and a series of dot separated identifiers immediately following the patch version. Identifiers MUST comprise only ASCII alphanumeric and hyphen [0-9A-Za-z-]. Identifiers MUST NOT be empty. Numberic identifiers MUST NOT include leading zeros. Pre-release versions have a lower precedence than the associated normal version. A pre-release version indicates that the version is unstable and might not satisfy the intended compatibility requirements as denoted by its associated normal version. (Examples: 1.0.0-alpha, 1.0.0-alpha.1, 1.0.0-0.3.7, 1.0.0-x.7.z.92.) (You should probably keep it simple and mark it alpha.)
10. build metadata MAY be denoted by appending a plus sing (+) and a series of dot separated identifiers immediately following the patch or pre-release version. Identifiers MUST compirse only ASCII alphanumerics and hypen [0-9A-Za-z-]. Identifiers MUST NOT be empty. Build metadata MUST be ignored when determining version precedence. Thus two versions that differ only in the build meta data, have the same precedence. (Examples: 1.0.0-alpha+001, 1.0.0+20130313144700, 1.0.0-beta+exp.sha.5114f85.)
11. Precedence referes to how versions oare compared to each other when ordered. Precedence MUST be calculated by separating the versions in to major, minor, patch, and pre-release identifiers in that order (Build metadata does not figure into precedence. Precedence is determined by the first difference when comparing each of these identifiers from left to right as follows: Major, minor, and patch version are always compared numerically. (Example: 1.0.0 < 2.0.0 < 2.1.0 < 2.1.1). When major, minor, and patch are equal, a pre-release version has lower precedence than a normal version. (Example: 1.0.0-alpha < 1.0.0.) Precedence for two pre-release versions with the same major, minor, and patch version MUST be determined by comparing each dot separated identifier from left to right until a difference is found as follows: identifiers consisting of only digits are compared numerically and identifiers with letters or hyphens are compared lexically in ASCII sort order. Numeric identifiers always have lower precedence than non-numeric identifiers. A larger set of pre-release fields has a higher precedence than a smaller set, if all of the preceding identifiers are equal. Example: 1.0.0-alpha < 1.0.0-alpha.1 < 1.0.0-alpha.beta < 1.0.0-beta < 1.0.0-beta.2 < 1.0.0-beta.11 < 1.0.0-rc.1 < 1.0.0.)

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References

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#Documentation #NodeJS