JS split array of objects by object field

Question

I have an array of tokens:

[
    {type: 'name', value: 'foo'},
    {type: 'string', value: 'bar'},
    {type: 'special', value: ','},
    {type: 'name', value: 'buzz'}
]

And I'd like to split them by value equal to ,:

[
    [
        {type: 'name', value: 'foo'},
        {type: 'string', value: 'bar'}
    ],
    [
        {type: 'name', value: 'buzz'}
    ]
]

How should I do it?

What have you tried? What specifically do you need help with? — Carcigenicate
– Carcigenicate, Commented Dec 8, 2018 at 13:14
Well, the only thing that comes to mind is iterating through the array and putting the objects in an array inside that array, then when a comma is encountered, another array is started. There must be a better way, but I can't really wrap my head around it.. — Mateusz Sowiński
– Mateusz Sowiński, Commented Dec 8, 2018 at 13:16

Ori Drori · Accepted Answer · 2018-12-08 13:24:19Z

2

You can use Array.reduce() to iterate the items. There are three cases:

The item's value is , - add a new sub-array without the item.
There is no sub-array - add a new sub-array with the item.
The rest - add the item to the last sub-array.

const data = [
    {type: 'name', value: 'foo'},
    {type: 'string', value: 'bar'},
    {type: 'special', value: ','},
    {type: 'name', value: 'buzz'}
];

const result = data.reduce((r, o) => {
  if(o.value === ',') return [...r, []];
  if(!r.length) return [[o]];
  
  r[r.length - 1].push(o);
  
  return r;
}, []);

console.log(result);

answered Dec 8, 2018 at 13:24

Ori Drori

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Comments

Code Maniac · Accepted Answer · 2018-12-08 13:26:09Z

1

Using forEach

let arr = [
    {type: 'name', value: 'foo'},
    {type: 'string', value: 'bar'},
    {type: 'special', value: ','},
    {type: 'name', value: 'buzz'}
]

let op = [];
let temp = [];
arr.forEach((e,i)=>{
  if(e.value === ',' && temp.length){
    op.push(temp);
    temp =[];
  } else {
    temp.push(e);
  }
});
if(temp.length) op.push(temp);
console.log(op);

answered Dec 8, 2018 at 13:26

Code Maniac

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