Need to concat arrays( don't know how much would be) (js)

Question

Example view of my arr.

There need to concat deepest objects,

for example have 2 arrays [{id1:color:grey}] [{id4:color:grey},{id8:color:grey}]

in result need be this: [{id1:color:grey},{id4:color:grey},{id8:color:grey}]

try do something this but no idea how to concat, I don't know how much arrays can be

var kkk = [];

        for (var i=0; i < arrData.length;i++) {
          var his = arrData[i][1];
          for(var k=0; k < his.length; k++) {
            console.log(his[0])
          }

        }

what I must do in loop? and loop is correct?

My object :

Array[2]
0:"th"
1:Array[2]
   0:Array[1] //this need concat
   1:Array[1] //this need concat

["th"
,[[[{"id":4,"color":"grey"},
{"id":5,"color":"grey"},
{"id":6,"color":"grey"},
{"id":7,"color":"grey"},
{"id":8,"color":"grey"},
{"id":9,"color":"grey"},
{"id":10,"color":"grey"},
{"id":11,"color":"grey"},{"id":12,"color":"grey"}]],

[[{"id":19,"color":"grey"},{"id":20,"color":"grey"},{"id":21,"color":"grey"}

]]]]

you have nothing like `[{id1:color:grey}] [{id4:color:grey},{id8:color:grey}]` because that simply isn't valid - and when someone says "share your object" that doesn't mean a picture of it :p — Jaromanda X, Aug 24 '17 at 05:59
*Need to concat arrays*, you should look into `Array.concat`. — Rajesh, Aug 24 '17 at 06:00
Please `JSON.stringify()` your object and update the question. — Hassan Imam, Aug 24 '17 at 06:06
Possible duplicate of [Javascript Concat Multidimensional Array](https://stackoverflow.com/questions/44971357/javascript-concat-multidimensional-array) — Hassan Imam, Aug 24 '17 at 06:08
This operation is called "flatten". You should be able to search for "flatten" implementations. — 000, Aug 24 '17 at 06:08

score 1 · Accepted Answer · answered Aug 24 '17 at 06:14

You can flatten the array and then concatenate results into the array.

I used code from one of my repos.

var arr = [[[{color : "red", id : 1}]],[{color : "green", id : 2}],[[[{color : "yellow", id : 3}]]],[{color : "blue", id : 4}]];

const __flattenReducer = (result,value,valueIndex,arr)=>{
  if(value instanceof Array){
    return value.reduce(__flattenReducer,result);
  }else{
    result.push(value);
    return result;
  }
};

const flatten = function(arr){
   if(arr instanceof Array){
     return Array.prototype.reduce.apply(arr,[__flattenReducer,[]]);
   }else{
     throw new TypeError('Expected an array');
   }
}

console.log(flatten(arr))

Repeated pushing onto an array will be much less performant than Array.prototype.concat — 000, Aug 24 '17 at 13:43

score 0 · Answer 2 · answered Aug 24 '17 at 06:15

0

function flatten(arr) {
  if (Array.isArray(arr)) return 
Array.prototype.concat.apply([], arr.map(flatten));
  return arr;
}

This is the basic recursive solution for flatten.

answered Aug 24 '17 at 06:15

000

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Need to concat arrays( don't know how much would be) (js)

2 Answers2