FP practice

point-free.expression.rewrite.js

const id = 'archie_is_good_guy';
// you may change listSetting for testing.
const listSetting = [];

//original function.
const targetListSetting = listSetting.filter(dd=>{
  return id === dd.bfid || id === dd.name_list_id;
})[0];

//point-free experssion rewrite

//helper fn
const compose = (...fns) => x => fns.reduceRight((v, f) => f(v), x);
const flip = fn => (...fns) => fn(...fns.reverse());
const pipe = flip(compose);
const first = d => d[0];
const filter = predicate => d => d.filter(predicate);
const not = fn => x => !fn(x);
const and = fa => fb => x => fa(x) && fb(x);
const or = fn => fa => fb => x => fa(x) || fb(x);
const props = field => x => x[field];
const map = fn => x => x.map(fn);
const filter = fn => x => x.filter(fn);
const reduce = fn => x => x.reduce(fn);
const some = fn => x => x.some(fn);
const every = fn => x => x.every(fn);

//business logic
const MatchId = equal(id);
const getBfid = get('bfid');
const getNameListId = get('name_list_id');

//Q: write this fn 
const targetListPredicate = ... 

const getTargetListSetting = first(filter(targetListPredicate));
const targetListSetting = getTargetListSetting(listSetting)