Intersect and merge two array of objects

Question

I have two arrays:

var odd = [
    { name : "1", extraProp1 : "propValue1" },
    { name : "3",  extraProp1 : "propValue2"         


        

Answer 1

Indeed, in your attempt you are correctly filtering a, but you have no code that merges two objects.

I would also use a Map for faster lookup than with a nested call of filter:

function merge(a, b, prop) {
    let map = new Map(b.map(o => [o[prop], o]));
    return a.reduce((acc, o) => {
        let match = map.get(o[prop]);
        return match ? acc.concat({ ...o, ...match }) : acc;
    }, []);
}


var odd = [
    { name : "1", extraProp1 : "propValue1" },
    { name : "3",  extraProp1 : "propValue2"}
];

var even = [
    { name : "1", extraProp2 : "prop1" },
    { name : "2", extraProp2 : "prop2"},
    { name : "4", extraProp2 : "prop3" }
]; 

console.log(merge(odd, even, "name"));

The { ...o, ...match } part performs the actual merge of two objects that was missing in your solution.