Map Entries

Turn map entries into display text.

map_entries.js

const prefix = "A";
const names = Array.from(
  new Map([
    ["Ada", 2],
    ["Bo", 3],
    ["Cy", 4],
  ]).entries()
)
  .filter((entry) => entry[0].startsWith(prefix))
  .map((entry) => entry[0] + ":" + entry[1])
  .join(",");

console.log("prefix=" + prefix);
console.log("names=" + names);

map-entries `Map.entries()` returns pairs in insertion order. Convert those pairs with `Array.from(...)` when array methods make the next step clearer.