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Functional Programming Patterns With RamdaJS!

Get the Flavors: Solution Review

Solution review.

We'll cover the following...

So a given employee’s JSON is shaped like this

Javascript (babel-node)
{
    "name": "Devante",
    "username": "Devante40",
    "avatar": "https://s3.amazonaws.com/uifaces/faces/twitter/adrienths/128.jpg",
    "email": "Devante40_Trantow11@yahoo.com",
    "dob": "1958-06-01T03:53:42.127Z",
    "phone": "544.986.5264",
    "address": {
      "street": "Louie Mission",
      "suite": "Suite 504",
      "city": "Lake Kyle",
      "zipcode": "60316",
      "geo": {
        "lat": "-65.8775",
        "lng": "-66.4677"
      }
    },
    "website": "delaney.info",
    "company": {
      "name": "Keeling Group",
      "catchPhrase": "Self-enabling grid-enabled architecture",
      "bs": "real-time orchestrate interfaces"
    },
    "interests": {
      "foods": {
        "sweets": {
          "iceCream": {
            "favoriteFlavor": "White Chocolate Raspberry Truffle"
          }
        }
      }
    }
  }

And their flavor’s tucked away here

Javascript (babel-node)
"interests": {
  "foods": {
    "sweets": {
      "iceCream": {
        "favoriteFlavor": "White Chocolate Raspberry Truffle"
      }
    }
  }
}

That’s quite a few levels to go through, so Ramda’s path function is a good start.

Javascript (babel-node)
import { path } from 'ramda';
import data from './data.json';
const getFlavor = path([
  'interests',
  'foods',
  'sweets',
  'iceCream',
  'favoriteFlavor'
]);
const result = getFlavor(data);
console.log({ result });

Our solution must use lenses, so this can easily become a lensPath and view combination.

Javascript (babel-node)
import { lensPath, view } from 'ramda';
import data from './data.json';
const favoriteFlavor = lensPath([
  'interests',
  'foods',
  'sweets',
  'iceCream',
  'favoriteFlavor'
]);
const result = view(favoriteFlavor, data);
console.log({ result });

But this only works for one person! Using it on a list of people returns undefined because your using view on the array.

Javascript (babel-node)
import { lensPath, view } from 'ramda';
import employees from './employees.json';
const favoriteFlavor = lensPath([
  'interests',
  'foods',
  'sweets',
  'iceCream',
  'favoriteFlavor'
]);
const result = view(favoriteFlavor, employees);
console.log({ result });

How do we generalize a solution to a list?

Map

Javascript (babel-node)
import { lensPath, map, view } from 'ramda';
import employees from './employees.json';
const favoriteFlavor = lensPath([
  'interests',
  'foods',
  'sweets',
  'iceCream',
  'favoriteFlavor'
]);
const result = map(view(favoriteFlavor), employees);
console.log({ result });

As we previously discussed, lenses use map themselves. When they receive the data, they begin unfolding and traverse the data structure.

Adding map on top of that just loops through employees and feeds each one to view as data.

Our result is an array of everyone’s favorite flavor!