filter-map

filter-map

A filter function for JavaScript Maps. Constructs a new Map with every key-value pair from the given map that satisfies a given function.

You can get it with npm i filter-map.

const filterMap = require("filter-map");

const exampleMap = new Map([
    ["a", 1],
    ["b", 2],
    ["c", 3],
    ["d", 4]
]);

// Filter even-numbered values out of the Map.
const filteredMap = filterMap(exampleMap, (key, value) => value % 2);

filteredMap.has("a"); // true
filteredMap.has("b"); // false
filteredMap.has("c"); // true
filteredMap.has("d"); // false

filterMap takes a Map and a filtering function, and returns the newly constructed Map. The filtering function takes a key and a value, and can return any value, which is then casted to a Boolean to determine whether to filter the key-value pair.