How to keep only the paths to the leaves in a directory tree?

November 21, 2021

I have this array of directory paths (strings):

let arr = [
  '0',
  '2',
  '0\\0-1',
  '2\\2-0',
  '2\\2-0\\2-0-0',
  '2\\2-0\\2-0-0\\2-0-0-0',
  '2\\2-0\\2-0-0\\2-0-0-1'
]

The trees of directories would look like this (note that 0-1, 2-0-0-0, and 2-0-0-1 are the leaves):

0
|_ 0-1

2
|_ 2-0
   |_ 2-0-0
      |_ 2-0-0-0
      |_ 2-0-0-1

From this array, I want to keep only the paths to the leaves. This means that I want to remove all elements, except 0\0-1, 2\2-0\2-0-0\2-0-0-0, and 2\2-0\2-0-0\2-0-0-1. My new array should look like this:

newArr = [
  '0\\0-1',
  '2\\2-0\\2-0-0\\2-0-0-0',
  `2\\2-0\\2-0-0\\2-0-0-1`
]

How can I do this in JavaScript?

>Solution :

Suggested by DexieTheSheep, using startsWith

let arr = [
  '0',
  '2',
  '0\\0-1',
  '2\\2-0',
  '2\\2-0\\2-0-0',
  '2\\2-0\\2-0-0\\2-0-0-0',
  '2\\2-0\\2-0-0\\2-0-0-1'
];

const result = arr.filter(item => !arr.some(ex => ex.startsWith(item + '\\')));

console.log(result);