Confusion with JSON_DECODE second param - php

Question

I just created a small program to check JSON and JSON_FORCE_OBJECT
$tree = [
0 => array
(
'id' => 1,
'parent' => '0',
'name' => 'b',
'surname' => 'myfolder/b'
),
1 => array
(
'id' => 2,
'parent' => 1,
'name' => 'ignore',
'surname' => 'myfolder/ignore2'
),
2 => array
(
'id' => 3,
'parent' => 1,
'name' => 'ignore2',
'surname' => 'myfolder/ignore4'
)
];
var_dump($tree);
$try = json_encode($tree);//To print with key. Also if we decode we get result as object
//echo $try;
echo '<br />';
$try2 = json_decode($try,JSON_FORCE_OBJECT);
var_dump($try2);
$try2 is exactly equal to $tree an associative array.
Whereas if I remove JSON_FORCE_OBJECT from this line
$try2 = json_decode($try,JSON_FORCE_OBJECT);
I get an array with child object. Though JSON_FORCE_OBJECT is supposed to be used with json_encode but using it with json_decode, I get a surprising result. I am unable to understand whats going on inside?? I thought when I encode it and decode it I should get same result. But I got the same result only when I used JSON_FORCE_OBJECT. Can anyone please help why this happens?

Answer 1

According to the manual: http://php.net/manual/en/function.json-decode.php
json_decode returns an array of objects if you want to convert them in assoc array you should specify the second param which is a boolean
JSON_FORCE_OBJECT is an int with value 16...
when this is passed as second param php cast/converts it to its bool equivalent which true.
To test the above stated behavior try:
var_dump((bool)1; (bool)2, (bool)16)
//output bool(true) bool(true) bool(true) .
var_dump((bool)0)
//outputs bool(false)
So it's nothing to do with JSON_FORCE_OBJECT...even
json_decode($try,true);
json_decode($try,2);
json_decode($try,3);
json_decode($try,4);
json_decode($try,'someVar');
....
//should return your expected result (assoc array)
Similarly if you pass 0 as second param PHP will cast it into bool (which is false) and returns you an object
json_decode($try,0);
json_decode($try,false);
json_decode($try,null)
json_decode($try)
...
//will return objects

Answer 2

The second parameter to json_decode is a boolean. It accepts true or false. It does not accept JSON_FORCE_OBJECT. You're trying to use the wrong constant for the wrong function.
json_decode's 4th parameter accepts a bitmask of constants, but currently it only supports JSON_BIGINT_AS_STRING.
If you want to return stdClass instances for JSON objects from json_decode, set its second parameter to false (the default). Setting it to any non-falsey value makes it return associative arrays instead of objects. Setting it to JSON_FORCE_OBJECT counts as "not-falsey".
It's all described in the manual: http://php.net/json_decode