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---
id: 8d1923c8c441eddfaeb5bdef
title: Size of the Set
challengeType: 1
---
## Description
< section id = 'description' >
In this exercise we are going to create a size function for our Set. This function should be named < code > this.size< / code > and it should return the size of the collection.
< / section >
## Instructions
< section id = 'instructions' >
< / section >
## Tests
< section id = 'tests' >
```yml
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tests:
- text: Your < code > Set</ code > class should have a < code > size</ code > method.
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testString: assert((function(){var test = new Set(); return (typeof test.size === 'function')}()), 'Your < code > Set< / code > class should have a < code > size< / code > method.');
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- text: The < code > size</ code > method should return the number of elements in the collection.
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testString: assert((function(){var test = new Set(); test.add('a');test.add('b');test.remove('a');return (test.size() === 1)}()), 'The < code > size< / code > method should return the number of elements in the collection.');
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```
< / section >
## Challenge Seed
< section id = 'challengeSeed' >
< div id = 'js-seed' >
```js
function Set() {
// the var collection will hold the set
var collection = [];
// this method will check for the presence of an element and return true or false
this.has = function(element) {
return (collection.indexOf(element) !== -1);
};
// this method will return all the values in the set
this.values = function() {
return collection;
};
// this method will add an element to the set
this.add = function(element) {
if(!this.has(element)){
collection.push(element);
return true;
}
return false;
};
// this method will remove an element from a set
this.remove = function(element) {
if(this.has(element)){
var index = collection.indexOf(element);
collection.splice(index,1);
return true;
}
return false;
};
// change code below this line
// change code above this line
}
```
< / div >
< / section >
## Solution
< section id = 'solution' >
```js
function Set() {var collection = []; this.has = function(e){return(collection.indexOf(e) !== -1);};this.values = function() {return collection;};this.add = function(element) {if (!this.has(element)) {collection.push(element);return true;} else {return false;}};this.remove = function(element) {if(this.has(element)) {var i = collection.indexOf(element);collection.splice(i, 1);return true;}return false;};this.size = function() {return collection.length;};}
```
< / section >