freeCodeCamp/curriculum/challenges/english/02-javascript-algorithms-and-data-structures/object-oriented-programming/use-an-iife-to-create-a-module.english.md

---
id: 587d7db2367417b2b2512b8c
title: Use an IIFE to Create a Module
challengeType: 1
forumTopicId: 301332
---

## Description
<section id='description'>
An immediately invoked function expression (IIFE) is often used to group related functionality into a single object or <dfn>module</dfn>. For example, an earlier challenge defined two mixins:

```js
function glideMixin(obj) {
  obj.glide = function() {
    console.log("Gliding on the water");
  };
}
function flyMixin(obj) {
  obj.fly = function() {
    console.log("Flying, wooosh!");
  };
}
```

We can group these mixins into a module as follows:

```js
let motionModule = (function () {
  return {
    glideMixin: function(obj) {
      obj.glide = function() {
        console.log("Gliding on the water");
      };
    },
    flyMixin: function(obj) {
      obj.fly = function() {
        console.log("Flying, wooosh!");
      };
    }
  }
})(); // The two parentheses cause the function to be immediately invoked
```

Note that you have an immediately invoked function expression (IIFE) that returns an object <code>motionModule</code>. This returned object contains all of the mixin behaviors as properties of the object.
The advantage of the module pattern is that all of the motion behaviors can be packaged into a single object that can then be used by other parts of your code. Here is an example using it:

```js
motionModule.glideMixin(duck);
duck.glide();
```

</section>

## Instructions
<section id='instructions'>
Create a module named <code>funModule</code> to wrap the two mixins <code>isCuteMixin</code> and <code>singMixin</code>. <code>funModule</code> should return an object.
</section>

## Tests
<section id='tests'>

```yml
tests:
  - text: <code>funModule</code> should be defined and return an object.
    testString: assert(typeof funModule === "object");
  - text: <code>funModule.isCuteMixin</code> should access a function.
    testString: assert(typeof funModule.isCuteMixin === "function");
  - text: <code>funModule.singMixin</code> should access a function.
    testString: assert(typeof funModule.singMixin === "function");

```

</section>

## Challenge Seed
<section id='challengeSeed'>

<div id='js-seed'>

```js
let isCuteMixin = function(obj) {
  obj.isCute = function() {
    return true;
  };
};
let singMixin = function(obj) {
  obj.sing = function() {
    console.log("Singing to an awesome tune");
  };
};
```

</div>



</section>

## Solution
<section id='solution'>


```js
const funModule = (function () {
  return {
    isCuteMixin: obj => {
      obj.isCute = () => true;
    },
    singMixin: obj => {
      obj.sing = () => console.log("Singing to an awesome tune");
    }
  };
})();
```

</section>