objectMap(): Kind of Array.map() but for objects...

objectMap.js

// USAGE: objectMap(<object>, <callback>)
//        <object>: Any regular JavaScript object.
//        <callback>: function(<current_value>, <current_key>, <original_object>) {...}
// EXAMPLE:
//        objectMap({a: null, b: "23"}, Number) //-> { a: 0, b: 23 }
function objectMap(obj, cbk) {
    return Object.fromEntries(
        Object.entries(obj).map(
            ([key, value])=>[key, cbk(value, key, obj)]
        )
    );
};

objectWrapper.js

// Object enhancer adding methods that work like objectMap, but chainable.
// USAGE: enhancedObject = O(originalObject);
// EXAMPLE:
//       const myObj = O({foo: 2, bar: 1, baz: 0});
//       myObj
//          .filter(v=>!!v)       // {foo: 2, bar: 1}
//          .toKeySorted()        // {bar: 1, foo: 2}
//          .toSorted((a,b)=>b-a) // {foo: 2, bar: 1}
//          .map(String)          // {foo: "2", bar: "1"}
//       ;
const oParse = (obj, parser) => Object.fromEntries(parser(Object.entries(obj)));
class O extends Object {
    constructor(src, ...args) {
        super(...args);
        Object.assign(this, src);
    };
    map(cbk){
        return new O(oParse(this
            , entries=>entries.map(([key, value])=>[key, cbk(value, key, this)])
        ));
    };
    filter(cbk){
        return new O(oParse(this
            , entries=>entries.filter(([key, value])=>!!cbk(value, key, this))
        ));
    };
    toSorted(cbk=(a,b)=>(a<b?-1:a>b?1:0)){
        return new O(oParse(this
            , entries=>entries.sort(([,v1], [,v2])=>cbk(v1, v2))
        ));
    };
    toKeySorted(cbk=(a,b)=>(a<b?-1:a>b?1:0)){
        return new O(oParse(this
            , entries=>entries.sort(([k1], [k2])=>cbk(k1, k2))
        ));
    };
};

export const O = o=>new O(o);