TypeScriptでMap ⇔ Object変換 ref: https://qiita.com/kurogelee/items/8049c51a7c323ce0911e

util.ts

import * as _ from "lodash";

function mapToObj<V>(map: Map<number, V>): _.NumericDictionary<V>;
function mapToObj<V>(map: Map<string, V>): _.Dictionary<V>;
function mapToObj<V>(map: Map<any, V>): _.Dictionary<V> {
    return _.fromPairs([...map]);
}

function objToMap<V>(obj: _.NumericDictionary<V>): Map<number, V>;
function objToMap<V>(obj: _.Dictionary<V>): Map<string, V>;
function objToMap<V>(obj: _.Dictionary<V>): Map<any, V> {
    return new Map(Object.entries(obj));
}