Sort array string which begins with a letter

Question

How i can sort this array list to be sure all files starting with _ will be first?

Context: is for a loader and i want to be sure to load all files with _ first.

List are generate random from a scan, so i can never be sure about the order.

0:"js\game\global\app.js"
1:"js\game\global\camera.js"
2:"js\game\global\displayGroups.js"
3:"js\game\global\dataBase.js"
4:"js\game\global\mouse.js"
5:"js\game\global\loaders.js"
6:"js\game\global\stage.js"
7:"js\game\global\polyfill.js"
8:"js\game\scenes\scene_boot.js"
9:"js\game\scenes\scene_IntroVideo.js"
10:"js\game\scenes\scene_loader.js"
11:"js\game\scenes\scene_Map1.js"
12:"js\game\scenes\_scene_base.js" //need to be alway first
13:"js\game\scenes\scene_Title.js"

So in this example, after sorting, the file _scene_base should be first.

Here is my test code, but it is revealed unstable and I don't know why, sometime it not work.

 files.sort((a,b) => {return a.indexOf("\_")>-1?-files.indexOf(a):0 });

sorry if my english are poor guys.

Answer 1

Another solution based on indexOf and only the first position of the underscore.

const arr = [
  'js\\game\\global\\app.js',
  'js\\game\\global\\camera.js',
  'js\\game\\global\\displayGroups.js',
  'js\\game\\global\\dataBase.js',
  'js\\game\\global\\mouse.js',
  'js\\game\\global\\loaders.js',
  'js\\game\\global\\stage.js',
  'js\\game\\global\\polyfill.js',
  'js\\game\\scenes\\scene_boot.js',
  'js\\game\\scenes\\scene_IntroVideo.js',
  'js\\game\\scenes\\scene_loader.js',
  'js\\game\\scenes\\scene_Map1.js',
  'js\\game\\scenes\\scene_Title.js',
  'js\\game\\scenes\\_scene_base.js',
  'js\\game\\scenes\\scene_Loader.js',
  'js\\game\\scenes\\_scenebase.js',
  'js\\game\\scenes\\sceneTit_le.js',
  'js\\game\\scenes\\scene_introVide_o.js',
  'js\\game\\scenes\\sceneIntroVi_deo.js',
];

arr.sort((a, b) => {
   const ai = a.indexOf('_');
   const bi = b.indexOf('_');
   return (ai > -1 && bi > -1 && (ai - bi)) || -1;
});

console.log(arr)

Answer 2

If you want to place any file that starts with underscore first in order, filter and concatenate it.

const arr = ['js\\game\\global\\app.js',
  'js\\game\\global\\camera.js',
  'js\\game\\global\\displayGroups.js',
  'js\\game\\global\\dataBase.js',
  'js\\game\\global\\mouse.js',
  'js\\game\\global\\loaders.js',
  'js\\game\\global\\stage.js',
  'js\\game\\global\\polyfill.js',
  'js\\game\\scenes\\scene_boot.js',
  'js\\game\\scenes\\scene_IntroVideo.js',
  'js\\game\\scenes\\scene_loader.js',
  'js\\game\\scenes\\scene_Map1.js',
  'js\\game\\scenes\\_scene_base.js',
  'js\\game\\scenes\\scene_Title.js'
]

const _files = arr.filter(e => e.indexOf('\\_') !== -1).sort()
const files = arr.filter(e => e.indexOf('\\_') === -1).sort()

const arr2 = _files.concat(files)

console.log(arr2)