enforce valid JSDoc comments (valid-jsdoc)

The --fix option on the command line can automatically fix some of the problems reported by this rule.

JSDoc generates application programming interface (API) documentation from specially-formatted comments in JavaScript code. For example, this is a JSDoc comment for a function:

/**
 * Add two numbers.
 * @param {number} num1 The first number.
 * @param {number} num2 The second number.
 * @returns {number} The sum of the two numbers.
 */
function add(num1, num2) {
    return num1 + num2;
}

If comments are invalid because of typing mistakes, then documentation will be incomplete.

If comments are inconsistent because they are not updated when function definitions are modified, then readers might become confused.

Rule Details

This rule enforces valid and consistent JSDoc comments. It reports any of the following problems:

This rule does not report missing JSDoc comments for classes, functions, or methods.

Note: This rule does not support all of the Google Closure documentation tool’s use cases. As such, some code such as (/**number*/ n => n * 2); will be flagged as missing appropriate function JSDoc comments even though /**number*/ is intended to be a type hint and not a documentation block for the function. We don’t recommend using this rule if you use type hints in this way.

Examples of incorrect code for this rule:

/*eslint valid-jsdoc: "error"*/

// expected @param tag for parameter num1 but found num instead
// missing @param tag for parameter num2
// missing return type
/**
 * Add two numbers.
 * @param {number} num The first number.
 * @returns The sum of the two numbers.
 */
function add(num1, num2) {
    return num1 + num2;
}

// missing brace
// missing @returns tag
/**
 * @param {string name Whom to greet.
 */
function greet(name) {
    console.log("Hello " + name);
}

// missing parameter type for num1
// missing parameter description for num2
/**
 * Represents a sum.
 * @constructor
 * @param num1 The first number.
 * @param {number} num2
 */
function sum(num1, num2) {
    this.num1 = num1;
    this.num2 = num2;
}

Examples of correct code for this rule:

/*eslint valid-jsdoc: "error"*/
/*eslint-env es6*/

/**
 * Add two numbers.
 * @param {number} num1 The first number.
 * @param {number} num2 The second number.
 * @returns {number} The sum of the two numbers.
 */
function add(num1, num2) {
    return num1 + num2;
}

// default options allow missing function description
// return type `void` means the function has no `return` statement
/**
 * @param {string} name Whom to greet.
 * @returns {void}
 */
function greet(name) {
    console.log("Hello " + name);
}

// @constructor tag allows missing @returns tag
/**
 * Represents a sum.
 * @constructor
 * @param {number} num1 The first number.
 * @param {number} num2 The second number.
 */
function sum(num1, num2) {
    this.num1 = num1;
    this.num2 = num2;
}

// class constructor allows missing @returns tag
/**
 * Represents a sum.
 */
class Sum {
    /**
     * @param {number} num1 The first number.
     * @param {number} num2 The second number.
     */
    constructor(num1, num2) {
        this.num1 = num1;
        this.num2 = num2;
    }
}

// @abstract tag allows @returns tag without `return` statement
class Widget {
    /**
    * When the state changes, does it affect the rendered appearance?
    * @abstract
    * @param {Object} state The new state of the widget.
    * @returns {boolean} Is current appearance inconsistent with new state?
    */
    mustRender (state) {
        throw new Error("Widget subclass did not implement mustRender");
    }
}

// @override tag allows missing @param and @returns tags
class WonderfulWidget extends Widget {
    /**
     * @override
     */
    mustRender (state) {
        return state !== this.state; // shallow comparison
    }
}

Options

This rule has an object option:

prefer

Examples of additional incorrect code for this rule with sample "prefer": { "arg": "param", "argument": "param", "class": "constructor", "return": "returns", "virtual": "abstract" } options:

/*eslint valid-jsdoc: ["error", { "prefer": { "arg": "param", "argument": "param", "class": "constructor", "return": "returns", "virtual": "abstract" } }]*/
/*eslint-env es6*/

/**
 * Add two numbers.
 * @arg {int} num1 The first number.
 * @arg {int} num2 The second number.
 * @return {int} The sum of the two numbers.
 */
function add(num1, num2) {
    return num1 + num2;
}

/**
 * Represents a sum.
 * @class
 * @argument {number} num1 The first number.
 * @argument {number} num2 The second number.
 */
function sum(num1, num2) {
    this.num1 = num1;
    this.num2 = num2;
}

class Widget {
    /**
     * When the state changes, does it affect the rendered appearance?
     * @virtual
     * @argument {Object} state The new state of the widget.
     * @return {boolean} Is current appearance inconsistent with new state?
     */
    mustRender (state) {
        throw new Error("Widget subclass did not implement mustRender");
    }
}

preferType

Examples of additional incorrect code for this rule with sample "preferType": { "Boolean": "boolean", "Number": "number", "object": "Object", "String": "string" } options:

/*eslint valid-jsdoc: ["error", { "preferType": { "Boolean": "boolean", "Number": "number", "object": "Object", "String": "string" } }]*/
/*eslint-env es6*/

/**
 * Add two numbers.
 * @param {Number} num1 The first number.
 * @param {Number} num2 The second number.
 * @returns {Number} The sum of the two numbers.
 */
function add(num1, num2) {
    return num1 + num2;
}

/**
 * Output a greeting as a side effect.
 * @param {String} name Whom to greet.
 * @returns {void}
 */
function greet(name) {
    console.log("Hello " + name);
}

class Widget {
    /**
     * When the state changes, does it affect the rendered appearance?
     * @abstract
     * @param {object} state The new state of the widget.
     * @returns {Boolean} Is current appearance inconsistent with new state?
     */
    mustRender (state) {
        throw new Error("Widget subclass did not implement mustRender");
    }
}

requireReturn

Examples of additional incorrect code for this rule with the "requireReturn": false option:

/*eslint valid-jsdoc: ["error", { "requireReturn": false }]*/

// unexpected @returns tag because function has no `return` statement
/**
 * @param {string} name Whom to greet.
 * @returns {string} The greeting.
 */
function greet(name) {
    console.log("Hello " + name);
}

// add @abstract tag to allow @returns tag without `return` statement
class Widget {
    /**
     * When the state changes, does it affect the rendered appearance?
     * @param {Object} state The new state of the widget.
     * @returns {boolean} Is current appearance inconsistent with new state?
     */
    mustRender (state) {
        throw new Error("Widget subclass did not implement mustRender");
    }
}

Example of additional correct code for this rule with the "requireReturn": false option:

/*eslint valid-jsdoc: ["error", { "requireReturn": false }]*/

/**
 * @param {string} name Whom to greet.
 */
function greet(name) {
    console.log("Hello " + name);
}

requireReturnType

Example of additional correct code for this rule with the "requireReturnType": false option:

/*eslint valid-jsdoc: ["error", { "requireReturnType": false }]*/

/**
 * Add two numbers.
 * @param {number} num1 The first number.
 * @param {number} num2 The second number.
 * @returns The sum of the two numbers.
 */
function add(num1, num2) {
    return num1 + num2;
}

matchDescription

Example of additional incorrect code for this rule with a sample "matchDescription": ".+" option:

/*eslint valid-jsdoc: ["error", { "matchDescription": ".+" }]*/

// missing function description
/**
 * @param {string} name Whom to greet.
 * @returns {void}
 */
function greet(name) {
    console.log("Hello " + name);
}

requireParamDescription

Example of additional correct code for this rule with the "requireParamDescription": false option:

/*eslint valid-jsdoc: ["error", { "requireParamDescription": false }]*/

/**
 * Add two numbers.
 * @param {int} num1
 * @param {int} num2
 * @returns {int} The sum of the two numbers.
 */
function add(num1, num2) {
    return num1 + num2;
}

requireReturnDescription

Example of additional correct code for this rule with the "requireReturnDescription": false option:

/*eslint valid-jsdoc: ["error", { "requireReturnDescription": false }]*/

/**
 * Add two numbers.
 * @param {number} num1 The first number.
 * @param {number} num2 The second number.
 * @returns {number}
 */
function add(num1, num2) {
    return num1 + num2;
}

When Not To Use It

If you aren’t using JSDoc, then you can safely turn this rule off.

Further Reading

Version

This rule was introduced in ESLint 0.4.0.

Resources