How to use Lodash to merge two collections based on a key?

Question

I have two collections, and the objects have a common key \"userId\". As below:

var _= require(\'lodash\');

var a = [
  { userId:\"p1\", item:1},
  { userId         


        

Answer 1

Try this demo

var a = [{
    userId: "p1",
    item: 1
}, {
    userId: "p2",
    item: 2
}, {
    userId: "p3",
    item: 4
}];

var b = [{
    userId: "p1",
    profile: 1
}, {
    userId: "p2",
    profile: 2
}];

a.forEach(function (aitem) {
    b.forEach(function (bitem) {
        if(aitem.userId === bitem.userId) {
            _.assign(aitem, bitem);
        }
    });
});

console.log(a);