--- id: 587d7b88367417b2b2512b46 title: Set Default Parameters for Your Functions challengeType: 1 --- ## Description <section id='description'> In order to help us create more flexible functions, ES6 introduces <dfn>default parameters</dfn> for functions. Check out this code: <blockquote>function greeting(name = "Anonymous") {<br> return "Hello " + name;<br>}<br>console.log(greeting("John")); // Hello John<br>console.log(greeting()); // Hello Anonymous</blockquote> The default parameter kicks in when the argument is not specified (it is undefined). As you can see in the example above, the parameter <code>name</code> will receive its default value <code>"Anonymous"</code> when you do not provide a value for the parameter. You can add default values for as many parameters as you want. </section> ## Instructions <section id='instructions'> Modify the function <code>increment</code> by adding default parameters so that it will add 1 to <code>number</code> if <code>value</code> is not specified. </section> ## Tests <section id='tests'> ```yml tests: - text: 'The result of <code>increment(5, 2)</code> should be <code>7</code>.' testString: 'assert(increment(5, 2) === 7, "The result of <code>increment(5, 2)</code> should be <code>7</code>.");' - text: The result of <code>increment(5)</code> should be <code>6</code>. testString: 'assert(increment(5) === 6, "The result of <code>increment(5)</code> should be <code>6</code>.");' - text: default parameter <code>1</code> was used for <code>value</code>. testString: 'getUserInput => assert(getUserInput("index").match(/value\s*=\s*1/g), "default parameter <code>1</code> was used for <code>value</code>.");' ``` </section> ## Challenge Seed <section id='challengeSeed'> <div id='js-seed'> ```js const increment = (function() { "use strict"; return function increment(number, value) { return number + value; }; })(); console.log(increment(5, 2)); // returns 7 console.log(increment(5)); // returns 6 ``` </div> </section> ## Solution <section id='solution'> ```js // solution required ``` </section>