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@param

Syntax​

@param {type} name - description
@param {type} [name] - optional parameter
@param {type} [name=default] - optional with default value

Overview​

@param documents a function parameter's name, type, and description. All three parts are optional, but providing at least a name is strongly recommended.

The parameter type may be any JavaScript built-in (string, number, boolean, Object, Array, …), a type expression, or a JSDoc namepath to a symbol defined elsewhere in your codebase.

TypeScript Supported

TypeScript uses @param for type-checking JavaScript files, including optional param syntax like [name] and [name=default].

TypeScript docs →

Examples​

Name only​

/**
 * @param somebody
 */
function sayHello(somebody) {
  alert(`Hello ${somebody}`);
}

Name and type​

/**
 * @param {string} somebody
 */
function sayHello(somebody) {
  alert(`Hello ${somebody}`);
}

Name, type, and description​

/**
 * @param {string} somebody - Somebody's name.
 */
function sayHello(somebody) {
  alert(`Hello ${somebody}`);
}

Optional parameter​

Wrap the name in [square brackets] to mark a parameter as optional:

/**
 * @param {string} [somebody='World'] - Somebody's name.
 */
function sayHello(somebody = 'World') {
  alert(`Hello ${somebody}`);
}

Multiple types​

Use | to allow more than one type:

/**
 * @param {string|string[]} names - One or more names.
 */
function greetAll(names) {}

Object properties​

Document the properties of an Object parameter with dotted names:

/**
 * @param {Object} employee - The employee.
 * @param {string} employee.name - The employee's name.
 * @param {number} employee.department - The employee's department code.
 */
function hire(employee) {}

Repeatable parameter​

Prefix the type with ... to indicate the parameter is repeatable (rest parameter):

/**
 * @param {...string} names - One or more names.
 */
function greetAll(...names) {}

Destructured parameter​

/**
 * @param {Object} options
 * @param {string} options.host - The server hostname.
 * @param {number} [options.port=3000] - The server port.
 */
function connect({ host, port = 3000 }) {}

See also​

Official reference: jsdoc.app/tags-param