@lends

Table of Contents

• Syntax
• Overview
• Examples
• Related Links

Syntax

@lends <namepath>

Overview

The @lends tag allows you to document all the members of an object literal as if they were members of a symbol with the given name. You might want to do this if you are passing an object literal into a function that creates a named class from its members.

Examples

In this example, we want to use a helper function to make a class named Person, along with instance methods named initialize and say. This is similar to how some popular frameworks handle class creation.

// We want to document this as being a class
var Person = makeClass(
    // We want to document these as being methods
    {
        initialize: function(name) {
            this.name = name;
        },
        say: function(message) {
            return this.name + " says: " + message;
        }
    }
);

Without any comments, JSDoc won't recognize that this code creates a Person class with two methods. To document the methods, we must use a @lends tag in a doc comment immediately before the object literal. The @lends tag tells JSDoc that all the member names of that object literal are being "loaned" to a variable named Person. We must also add comments to each of the methods.

The following example gets us closer to what we want:

/** @class */
var Person = makeClass(
    /** @lends Person */
    {
        /**
         * Create a `Person` instance.
         * @param {string} name - The person's name.
         */
        initialize: function(name) {
            this.name = name;
        },
        /**
         * Say something.
         * @param {string} message - The message to say.
         * @returns {string} The complete message.
         */
        say: function(message) {
            return this.name + " says: " + message;
        }
    }
);

Now the functions named initialize and say will be documented, but they appear as static methods of the Person class. That is possibly what you meant, but in this case we want initialize and say to belong to the instances of the Person class. So we change things slightly by lending the methods to the class's prototype:

/** @class */
var Person = makeClass(
    /** @lends Person.prototype */
    {
        /**
         * Create a `Person` instance.
         * @param {string} name - The person's name.
         */
        initialize: function(name) {
            this.name = name;
        },
        /**
         * Say something.
         * @param {string} message - The message to say.
         * @returns {string} The complete message.
         */
        say: function(message) {
            return this.name + " says: " + message;
        }
    }
);

One final step: Our class framework uses the loaned initialize function to construct Person instances, but a Person instance does not have its own initialize method. The solution is to add the @constructs tag to the loaned function. Remember to remove the @class tag as well, or else two classes will be documented.

var Person = makeClass(
    /** @lends Person.prototype */
    {
        /**
         * Create a `Person` instance.
         * @constructs
         * @param {string} name - The person's name.
         */
        initialize: function(name) {
            this.name = name;
        },
        /**
         * Say something.
         * @param {string} message - The message to say.
         * @returns {string} The complete message.
         */
        say: function(message) {
            return this.name + " says: " + message;
        }
    }
);

Related Links

• @borrows
• @constructs