Array.flatMap

Map each item to an array, then flatten one level into a single list.

flatMap is like map followed by flat(1). Handy when each row has nested lists (tags, roles).

Players with tags


        

        

          
Result

          

        

      

      
Flatten nested tag arrays.

    


    

      
Important JavaScript

      
const players = [
  { name: "Ava", tags: ["guard", "starter"] },
  { name: "Ben", tags: ["forward"] },
  { name: "Cara", tags: ["forward", "starter"] }
];

const tags = players.flatMap((player) => player.tags);
// ["guard", "starter", "forward", "forward", "starter"]

// Same idea in two steps:
// players.map((p) => p.tags).flat()

const unique = [...new Set(tags)];