Flatten a nested array of objects over a array field

Question

Have an object a1 =

[{name:\'x\',age:21, addr:[{flat:1,add:\'xyz\'},{flat:2,add:\'xsr\'}]},
{name:\'y\',age:22, addr:[{flat:3,add:\'xyz1\'},{flat:4,add:\'xsr1\'}         


        

Answer 1

Map every item in the original array to a new array, with a number of items according to the number of addr fields. Using concat flatten everything to a new array.

You can create new items using Object.assign() if you're transpiling to ES5 with babel or similar, as it's not supported by IE. However, since you're using angular, you can use angular.extend instead.

ES5:

var arr = [
  {name:'x',age:21, addr:[{flat:1,add:'xyz'},{flat:2,add:'xsr'}]},
  {name:'y',age:22, addr:[{flat:3,add:'xyz1'},{flat:4,add:'xsr1'}]}
];
   
var result = [].concat.apply([], arr.map(function(item) {     
  return item.addr.map(function(addr) {
    return angular.extend({}, item, { addr: addr });
  });
}));

console.log(result);

ES6:

const arr = [
  {name:'x',age:21, addr:[{flat:1,add:'xyz'},{flat:2,add:'xsr'}]},
  {name:'y',age:22, addr:[{flat:3,add:'xyz1'},{flat:4,add:'xsr1'}]}
];
   
const result = [].concat(...arr.map((item) => item.addr.map((addr) => Object.assign({}, item, { addr }))));

console.log(result);