ThreadItJS transform performed using Ramda

threaditjs-ramda-transform.js

// Build the pipelines
const isRoot = where({ parentId: isNil });
const isNotRoot = complement(isRoot);

const assembleLookup = (accumulator, current) => {
  const key = current.parentId;
  const lookup  = compose(append(current), propOr([], key));
  
  return assoc(key, lookup(accumulator), accumulator);
}; 

const lookupPipeline = compose(reduce(assembleLookup, {}), filter(isNotRoot));

const transform = curry(data => ({
  lookups: lookupPipeline(data),
  root: find(isRoot, data)
}));

// Apply the data to the pipeline 
const input = [
  { id: 1 },
  { id: 2, parentId: 1 },
  { id: 3, parentId: 2 },
  { id: 4, parentId: 2 },
  { id: 5, parentId: 3 }
];

transform(input);