How to extend a typedef parameter in JSDOC?

Question

Assuming you have the following code inside a ES6 class (documentation):

/**
 * @typedef Test~options
 * @type {object.<string>}
 * @property {array} elements - An array containing elements
 * @property {number} length - The array length
 */

/**
 * @param  {Test~options} opt - Option object
 */
test(opt){

}

Now I would like to document another function, let's name it test2 . This function takes exactly the same options object, but needs another property parent .

How to document this without documenting redundant options? Redundant means:

/**
 * @typedef Test~options
 * @type {object.<string>}
 * @property {array} elements - An array containing elements
 * @property {number} length - The array length
 */

/**
 * @param  {Test~options} opt - Option object
 */
test(opt){

}


/**
 * @typedef Test~options2
 * @type {object.<string>}
 * @property {array} elements - An array containing elements
 * @property {number} length - The array length
 * @property {object} parent - The parent element
 */

/**
 * @param  {Test~options2} opt - Option object
 */
 test2(opt){

 }

Answer 1

Try it

/**
 * @typedef {object.<string>} Test~options
 * @property {array} elements - An array containing elements
 * @property {number} length - The array length
 */

/**
 * @param {Test~options} opt - Option object
 */
test(opt){

}

/**
 * @typedef {Test~options} Test~options2
 * @property {object} parent - The parent element
 */

/**
 * @param  {Test~options2} opt - Option object
 */
test2(opt){

}

Answer 2

I found this solution and this works very fine for me. originally from here

 /**
 * @typedef {Object} ChildType
 * @property {String} childProp
 *
 * @typedef {Base & ChildType} Child
 */

Answer 3

I don't like half-baked answers without a "full setup", so here is one:

/**
 * @typedef {Object} Person
 * @property {string} name - The person's name
 * @property {number} age - The person's age
 */
/**
 * @typedef {Object} WizardProperties
 * @property {string[]} magicPowers
 * @typedef {Person & WizardProperties} Wizard
 */
/** @type {Wizard} */
export const wizard = {
    name: "Harry",
    age: 20,
    magicPowers: ["brroooomm"]
}

It also works across multiple files, but you have to use the import('./person').Person style:

• person.mjs :

/**
 * @typedef {Object} Person
 * @property {string} name - The person's name
 * @property {number} age - The person's age
 */

• wizard.mjs :

/**
 * @typedef {Object} WizardProperties
 * @property {string[]} magicPowers
 * @typedef {import('./person').Person & WizardProperties} Wizard
 */
/** @type {Wizard} */
export const wizard = {
  name: "Harry",
  age: 20,
  magicPowers: ["brroooomm", "wheeeeeeeeeeeew"]
}