We'll learn how to take advantage of Ramda's automatic function currying and data-last argument order to combine a series of pure functions into a left-to-right composition, or pipeline, with Ramda's pipe function.
A simple example will take 'teams' array and output the best score team's name. We use 'R.sort', 'R.head' and 'R.prop' to get job done:
const teams = [
{name: 'Lions', score: 5},
{name: 'Tigers', score: 4},
{name: 'Bears', score: 6},
{name: 'Monkeys', score: 2},
]; const getTopName = function(teams){
const sorted = R.sort( (a,b) => b.score > a.score, teams);
const bestTeam = R.head(sorted);
const name = R.prop('name', bestTeam);
return name;
} const result = getTopName(teams)
console.log(result)
One thing in Ramda which is really cool that, for example, 'R.sort' takes two arguements, if you don't passin the second arguement which is 'teams', it will then return a function, so that it enable you currying function and take second arguement as param.
const teams = [
{name: 'Lions', score: 5},
{name: 'Tigers', score: 4},
{name: 'Bears', score: 6},
{name: 'Monkeys', score: 2},
]; const getBestTeam = R.sort( (a,b) => b.score > a.score);
const getTeamName = R.prop('name');
const getTopName = function(teams){
const sorted = getBestTeam(teams);
const bestTeam = R.head(sorted);
const name = getTeamName(bestTeam);
return name;
} const result = getTopName(teams)
console.log(result)
We will still get the same result.
Use 'R.pipe' to chain function together
In functional programming or lodash (_.chain), we get used to write chain methods, in Ramda, we can use R.pipe():
const teams = [
{name: 'Lions', score: 5},
{name: 'Tigers', score: 4},
{name: 'Bears', score: 6},
{name: 'Monkeys', score: 2},
]; const getBestTeam = R.sort( (a,b) => b.score > a.score);
const getTeamName = R.prop('name');
const getTopName = R.pipe(
getBestTeam,
R.head,
getTeamName
); /*
const getTopName = function(teams){
const sorted = getBestTeam(teams);
const bestTeam = R.head(sorted);
const name = getTeamName(bestTeam);
return name;
}*/ const result = getTopName(teams)
console.log(result)