Groups an array of items alphabetically, putting items that start with numbers in a '0-9' group.

groupAlphaArray.example.txt

let arrayToGroup = ['Alpha','Alpha2','Centaur','Dudeman', 'Ladygirl', '888','999','&^%$'];
groupAlphaArray(arrayToGroup)

/****OUPUT****/
[
   {
      "group":"A",
      "children":["Alpha","Alpha2"]
   },
   {
      "group":"C",
      "children":["Centaur"]
   },
   {
      "group":"D",
      "children":["Dudeman"]
   },
   {
      "group":"L",
      "children":["Ladygirl"]
   },
   {
      "group":"0-9",
      "children":["888","999","&^%$"]
   }
]

groupAlphaArray.js

function groupAlphaArray(rawData) {
    var numtest = new RegExp(/[^A-Za-z]/)
    let data = rawData.reduce((r,e)=>{
        let group = e.charAt(0).toUpperCase();
        numtest.test(group)?group = '0-9':group;
      
            if (!r[group]) {
               
                r[group] = {
                    group,
                    children: [e]
                }
            } else {
                r[group].children.push(e);
            }
    
        return r;
    }
    , {})
    let result = Object.values(data)
    return result
}