array.groupBy in TypeScript

Question

The basic array class has .map, .forEach, .filter, and .reduce, but .groupBy i noticably absent, preventing me f

Answer 1

you could add the function to the array prototype in your app (note some don't recomend this: Why is extending native objects a bad practice?):

Array.prototype.groupBy = function(/* params here */) { 
   let array = this; 
   let result;
   /* do more stuff here*/
   return result;
}; 

Then create an interface in typescript like this:

.d.ts version:

    interface Array
    {
        groupBy(func:(x:T) => string): Group[]
    }

OR in a normal ts file:

declare global {
   interface Array
   {
      groupBy(func:(x:T) => string): Group[]
   }
}

Then you can use:

 props.tags.groupBy((t)=>t.category_name)
     .map((group)=>{
                    [...]
                })