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

ES6+ version without lodash.

 const array1 = [{ userId: "p1", item: 1 },  { userId: "p2", item: 2 },{ userId: "p3", item: 4 }];
const array2 = [{ userId: "p1", profile: 1 }, { userId: "p2", profile: 2 }];


const result = array1.map(a => ({
  ...a,
  ...array2.find(b => b.userId === a.userId) // _.find(array2, 'skuId') <-- or with lodash 
}));

 document.write('
' + JSON.stringify(result, 0, 2) + '
');