2018-09-30 23:01:58 +01:00 
										
									 
								 
							 
							
								
							 
							
								 
							
							
								---
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								id: 587d7b88367417b2b2512b46
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								title: Set Default Parameters for Your Functions
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								challengeType: 1
							 
						 
					
						
							
								
									
										
										
										
											2019-08-05 09:17:33 -07:00 
										
									 
								 
							 
							
								
									
										 
								
							 
							
								 
							
							
								forumTopicId: 301209
							 
						 
					
						
							
								
									
										
										
										
											2018-09-30 23:01:58 +01:00 
										
									 
								 
							 
							
								
							 
							
								 
							
							
								---
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								## 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:
							 
						 
					
						
							
								
									
										
										
										
											2019-05-17 06:20:30 -07:00 
										
									 
								 
							 
							
								
									
										 
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								```js
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								function greeting(name = "Anonymous") {
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								  return "Hello " + name;
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								}
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								console.log(greeting("John")); // Hello John
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								console.log(greeting()); // Hello Anonymous
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								```
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
									
										
										
										
											2018-09-30 23:01:58 +01:00 
										
									 
								 
							 
							
								
							 
							
								 
							
							
								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
							 
						 
					
						
							
								
									
										
										
										
											2018-10-04 14:37:37 +01:00 
										
									 
								 
							 
							
								
									
										 
								
							 
							
								 
							
							
								tests:
							 
						 
					
						
							
								
									
										
										
										
											2018-10-20 21:02:47 +03:00 
										
									 
								 
							 
							
								
									
										 
								
							 
							
								 
							
							
								  -  text: The result of < code > increment(5, 2)</ code >  should be < code > 7</ code > .
							 
						 
					
						
							
								
									
										
										
										
											2019-03-25 19:49:34 +05:30 
										
									 
								 
							 
							
								
									
										 
								
							 
							
								 
							
							
								    testString: assert(increment(5, 2) === 7);
							 
						 
					
						
							
								
									
										
										
										
											2018-10-04 14:37:37 +01:00 
										
									 
								 
							 
							
								
									
										 
								
							 
							
								 
							
							
								  -  text: The result of < code > increment(5)</ code >  should be < code > 6</ code > .
							 
						 
					
						
							
								
									
										
										
										
											2019-03-25 19:49:34 +05:30 
										
									 
								 
							 
							
								
									
										 
								
							 
							
								 
							
							
								    testString: assert(increment(5) === 6);
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								  -  text: Default parameter < code > 1</ code >  was used for < code > value</ code > .
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								    testString: assert(code.match(/value\s*=\s*1/g));
							 
						 
					
						
							
								
									
										
										
										
											2018-09-30 23:01:58 +01:00 
										
									 
								 
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								```
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								< / section >  
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								## Challenge Seed
  
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								< section  id = 'challengeSeed' >  
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								< div  id = 'js-seed' >  
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								```js
							 
						 
					
						
							
								
									
										
										
										
											2019-03-25 19:49:34 +05:30 
										
									 
								 
							 
							
								
									
										 
								
							 
							
								 
							
							
								const increment = (number, value) => number + value;
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
									
										
										
										
											2018-09-30 23:01:58 +01:00 
										
									 
								 
							 
							
								
							 
							
								 
							
							
								console.log(increment(5, 2)); // returns 7
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								console.log(increment(5)); // returns 6
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								```
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								< / div >  
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								< / section >  
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								## Solution
  
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								< section  id = 'solution' >  
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								```js
							 
						 
					
						
							
								
									
										
										
										
											2019-03-25 19:49:34 +05:30 
										
									 
								 
							 
							
								
									
										 
								
							 
							
								 
							
							
								const increment = (number, value = 1) => number + value;
							 
						 
					
						
							
								
									
										
										
										
											2018-09-30 23:01:58 +01:00 
										
									 
								 
							 
							
								
							 
							
								 
							
							
								```
							 
						 
					
						
							
								
									
										
										
										
											2019-07-18 08:24:12 -07:00 
										
									 
								 
							 
							
								
									
										 
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
									
										
										
										
											2018-09-30 23:01:58 +01:00 
										
									 
								 
							 
							
								
							 
							
								 
							
							
								< / section >