JavaScript: Map Filter
Here is a function that filters map object.
/* [ Returns a new map where f(key,value) returns true. http://xahlee.info/js/js_map_filter.html Version 2018-04-13 ] */ const xah_map_filter = ((map_obj, f) => { const result = new Map(); for (let [k, v] of map_obj) if (f(k, v)) result.set(k, v); return result; }); // ssss--------------------------------------------------- // test const mp = new Map([[3, "n3"], [4, "n4"]]); console.log(xah_map_filter(mp, ((k, v) => ((v === "n4") ? true : false)))); // Map { 4 => "n4" }