Implement run-length encoding and decoding.

Run-length encoding (RLE) is a simple form of data compression, where runs (consecutive data elements) are replaced by just one data value and count.

For example we can represent the original 53 characters with only 13.

"WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWB"  ->  "12WB12W3B24WB"

RLE allows the original data to be perfectly reconstructed from the compressed data, which makes it a lossless data compression.

"AABCCCDEEEE"  ->  "2AB3CD4E"  ->  "AABCCCDEEEE"

For simplicity, you can assume that the unencoded string will only contain the letters A through Z (either lower or upper case) and whitespace. This way data to be encoded will never contain any numbers and numbers inside data to be decoded always represent the count for the following character.

Go through the setup instructions for JavaScript to install the necessary dependencies:

http://exercism.io/languages/javascript/installation

Execute the tests with:

jasmine <exercise-name>.spec.js

Replace <exercise-name> with the name of the current exercise. E.g., to test the Hello World exercise:

jasmine hello-world.spec.js

In many test suites all but the first test have been skipped.

Once you get a test passing, you can unskip the next one by changing xit to it.

Wikipedia https://en.wikipedia.org/wiki/Run-length_encoding

It's possible to submit an incomplete solution so you can see how others have completed the exercise.