funfunfunction_recursion_7fp.js

/*
https://www.youtube.com/watch?v=k7-N8R0-KY4&list=PL0zVEGEvSaeEd9hlmCXrk5yUyqUag-n84
@Gegeg
Could you do this with reduce?
*/

const categories = [
	{ id: 'a', parent: '0'},
	{ id: 'b', parent: '0'},
	{ id: 'c', parent: 'a'},
	{ id: 'd', parent: 'a'},
	{ id: 'e', parent: 'd'},
	{ id: 'f', parent: 'e'},
	{ id: 'g', parent: 'f'}
]

const mkTree = id => categories.filter(
  e => e.parent === id
).reduce((acc, last) => {
	acc[last.id] = mkTree(last.id)
	return acc
},{})

console.log(mkTree('0'), null, 2)