Question

You can pass a boolean to json_decode to return an array instead of an object

json_decode('{"foo", "bar", "baz"}', true);  // array(0 => 'foo', 1 => 'bar', 2 => 'baz')

My question is this. When parsing object literals, does this guarantee that the ordering of the items will be preserved? I know JSON object properties aren’t ordered, but PHP arrays are. I can’t find anywhere in the PHP manual where this is addressed explicitly. It probably pays to err on the side of caution, but I would like to avoid including some kind of “index” sub-property if possible.

Answer 1

Wouldn’t it make more sense in this case to use an array when you pass the JSON to PHP. If you don’t have any object keys in the JSON (which become associative array keys in PHP), just send it as an array. That way you will be guaranteed they will be in the same order in PHP as in javascript.

json_decode('{["foo", "bar", "baz"]}');
json_decode('["foo", "bar", "baz"]'); //I think this would work

If you need associative arrays (which is why you are passing the second argument as true), you will have to come up with some way to maintain their order when passing. You will pry have to do some post-processing on the resulting array after you decode it to format it how you want it.

$json = '{[ {"key" : "val"}, {"key" : "val"} ]}';
json_decode($json, true);