74. implement Observable Transformation Operators
easy - accepted / - tried
This is a follow-up on 57. create an Observable.
There are a lot of operators for Observable, if we think of Observable as event stream, then modifying the stream is a common task, transformation operators are useful at this.
In this problem, you are asked to implement map(), as the name indicates, it maps the value to another value thus creating a new event stream.
Here is an example.
const source = Observable.from([1,2,3]) map(x => x * x)(source) // this transformer doubles numbers and create a new stream .subscribe(console.log) // 1 // 4 // 9
pipe() method which could make this more readable.
const source = Observable.from([1,2,3]) source.pipe(map(x => x * x)) .subscribe(console.log) // 1 // 4 // 9
Note Observable is already given for you, no need to create it.