Decomposition

Decomposition is the process of breaking complex task into smaller simpler tasks. It makes it easier to understand, manage and extend the software over a period of time. These smaller steps will be then combined and deliver a complete solution.

In example below we are stimulating asynchronous request call to fetch data and breaking the response handler into smaller tasks with distinguished purpose.

We implemented a transformation and filtering handler to process the response instead of one single handler to do all the work.

const stimulatePromise = (value = [], timeout = 1500) => {
  return new Promise((res, rej) => {
    setTimeout(() => {
      res(value);
    }, timeout);
  });
};

const filterResponse = (response) => response.filter((i) => true);

const transformResponse = (response) => response.map((i) => i);

const fetchData = () => stimulatePromise();

fetchData().then(filterResponse).then(transformResponse);