- var_dump: documentation ( source)
- array_merge: documentation ( source)
<?php
$a = [];
$b = [['id'=>'foo'],['id'=>'bar']];
$c = [['id'=>'biz'],['id'=>'baz']];
$result = [['id'=>'foo'],['id'=>'bar'],['id'=>'biz'],['id'=>'baz']];
$d = array_merge($a,$b,$c);
var_dump($d === $result, $d);