lodash group by

lodash_group_by.js

const _ = require('lodash');
var obj = [
  { x: 1, x1: 123, a: 2, b: 3 },
  { x: 2, x1: 5432, a: 4, b: 23 },
  { x: 1, x1: 123, a: 123, b: 324 },
];

var common_column = ['x', 'x1'];
var result = _.chain(obj)
  .groupBy('x')
  .map((e) => ({
    ..._.pick(_.first(e), common_column),
    list: e.map((e) => _.omit(e, common_column)),
  }))
  .value();
console.log(obj);
console.log(JSON.stringify(result, null, '  '));
/*

[ { x: 1, x1: 123, a: 2, b: 3 },
  { x: 2, x1: 5432, a: 4, b: 23 },
  { x: 1, x1: 123, a: 123, b: 324 } ]
[
  {
    "x": 1,
    "x1": 123,
    "list": [
      {
        "a": 2,
        "b": 3
      },
      {
        "a": 123,
        "b": 324
      }
    ]
  },
  {
    "x": 2,
    "x1": 5432,
    "list": [
      {
        "a": 4,
        "b": 23
      }
    ]
  }
]

*/