Filtering Eloquent collection data with $collection->filter()

The collection's filter method calls array_filter on the underlying array, which, according to the PHP docs, preserves the array keys. This then results in your array being converted to a JavaScript object instead of an array.

Call values() on your collection to reset the keys on the underlying array:

$filtered_collection = $collection->filter(function ($item) {
    return $item->isDog();
})->values();

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Side note: in newer versions of Laravel, you can use a higher order message to shorten the above into this:

$filtered_collection = $collection->filter->isDog()->values();

Filtering from database could be done in this method also.

 //request the form value 
  $name=$request->name;
  $age=$request->age;
  $number=$request->phone;

 //write a query to filter
 $filter_result = DB::table('table_name')

 ->where('name', 'like', '%'.$name.'%')
 ->orWhere('age', 'like', '%'.$age.'%')
 ->orWhere('phone', 'like', '%'.$number.'%')

 ->get();

 if(is_null($filter_result)){
 return redirect()->back()->with('message',"No Data Found");

}else{
      return view('resultpage',compact('filter_result'));
}

Just convert it to JSON with keeping in mind what the Laravel documentation states:

Note: When filtering a collection and converting it to JSON, try calling the values function first to reset the array's keys.

So the final code would be:

$filtered_collection->values()->toJson();