The add method checks if a value already exists in the set, if not, then it adds that value to the set. We can implement it as follows −
Example
add(val) { if (!this.has(val)) { this.container[val] = val; return true; } return false; }
You can test this using −
Example
const testSet = new MySet(); testSet.add(1); testSet.add(2); testSet.add(5); testSet.add(2); testSet.display(); console.log(testSet.has(5)); console.log(testSet.has(20)); console.log(testSet.has(1));
Output
This will give the output −
{ '1': 1, '2': 2, '5': 5 } True False True
Note that even though we tried adding 2 twice, it only got added once. If you try logging it, you'll get a false. This is because of the values we're returning if we don't add it.
In ES6, you use the add function as follows −
Example
const testSet = new MySet(); testSet.add(1); testSet.add(2); testSet.add(5); testSet.add(2); console.log(testSet.has(5)); console.log(testSet.has(20)); console.log(testSet.has(1));
Output
This will give the output −
True False True