freeCodeCamp/curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-javascript/write-reusable-javascript-with-functions.md

---
id: 56bbb991ad1ed5201cd392cf
title: Write Reusable JavaScript with Functions
challengeType: 1
videoUrl: 'https://scrimba.com/c/cL6dqfy'
forumTopicId: 18378
dashedName: write-reusable-javascript-with-functions
---

# --description--

In JavaScript, we can divide up our code into reusable parts called <dfn>functions</dfn>.

Here's an example of a function:

```js
function functionName() {
  console.log("Hello World");
}
```

You can call or <dfn>invoke</dfn> this function by using its name followed by parentheses, like this: `functionName();` Each time the function is called it will print out the message `Hello World` on the dev console. All of the code between the curly braces will be executed every time the function is called.

# --instructions--

<ol>
  <li>
    Create a function called <code>reusableFunction</code> which prints the string <code>Hi World</code> to the dev console.
  </li>
  <li>
    Call the function.
  </li>
</ol>

# --hints--

`reusableFunction` should be a function.

```js
assert(typeof reusableFunction === 'function');
```

If `reusableFunction` is called, it should output the string `Hi World` to the console.

```js
assert(testConsole());
```

You should call `reusableFunction` once it is defined.

```js
const functionStr = reusableFunction && __helpers.removeWhiteSpace(reusableFunction.toString());
const codeWithoutFunction = __helpers.removeWhiteSpace(code).replace(/reusableFunction\(\)\{/g, '');
assert(/reusableFunction\(\)/.test(codeWithoutFunction));
```

# --seed--

## --after-user-code--

```js

function testConsole() {
  var logOutput = "";
  var originalConsole = console;
  var nativeLog = console.log;
  var hiWorldWasLogged = false;
  console.log = function (message) {
    if(message === 'Hi World')  {
      console.warn(message)
      hiWorldWasLogged = true;
    }
    if(message && message.trim) logOutput = message.trim();
    if(nativeLog.apply) {
      nativeLog.apply(originalConsole, arguments);
    } else {
      var nativeMsg = Array.prototype.slice.apply(arguments).join(' ');
      nativeLog(nativeMsg);
    }
  };
  reusableFunction();
  console.log = nativeLog;
  return hiWorldWasLogged;
}

```

## --seed-contents--

```js

```

# --solutions--

```js
function reusableFunction() {
  console.log("Hi World");
}
reusableFunction();
```