Ajax return array shows [object Object],[object Object] in PHP

Question

Within Jquery I am creating two arrays, one embedded in the other, like so....

arrayOne = [{name:'a',value:1}, {name:'b',value:2}]
var arrayTwo = [{name:'foo',value:'blah'},{name:'arrayOne',value:arrayOne}];

I am then putting this though Ajax and extracting the variable via PHP on the other side. The results of a print_r($arrayTwo) are as follows...

Array([foo] => blah [arrayOne] => [object Object],[object Object])

I can see no way of extracting the contents of arrayOne, which is a pity because I really need them! Can anyone tell me what I am doing wrong in Jquery or what I need to do in PHP to make the embedded array accessible.

Many thanks as always

---

Edit to add my Ajax code....

$.ajax({
  type: "POST",
  url:'actions.php',
  data:arrayTwo,
  datatype:'json',
  cache: false,
  success: function(data){

}

})

Answer 1

The issue is that jQuery's $.ajax (or rather $.param ) method treats an array of objects in a special way. jQuery will use name as the parameter name and the string representation of value as value:

> $.param([{name: 'foo', value: 42}, {name: 'bar', value: 21}])
"foo=42&bar=21"

But the string representation of arrayOne is the useless stuff you are seeing on the server:

> [{name:'a',value:1}, {name:'b',value:2}].toString()
"[object Object],[object Object]"

The documentation actually points out the caveats when passing an array / object:

If the object passed is in an Array, it must be an array of objects in the format returned by .serializeArray()

 [ { name: "first", value: "Rick" }, { name: "last", value: "Astley" }, { name: "job", value: "Rock Star" } ] 

Note : Because some frameworks have limited ability to parse serialized arrays, developers should exercise caution when passing an obj argument that contains objects or arrays nested within another array.

Note : Because there is no universally agreed-upon specification for param strings, it is not possible to encode complex data structures using this method in a manner that works ideally across all languages supporting such input. Use JSON format as an alternative for encoding complex data instead.

---

Since you have a complex data structure, you should probably use JSON to encode your data:

data: {data: JSON.stringify(arrayTwo)},

and on the server you simply decode it with

$data = json_decode($_POST['data'], true);

$data will have the exact same structure as arrayTwo .

But in case you want to actually have parameters with names foo and arrayOne , then you only need to serialize the the value of arrayOne :

data:  [
  {name:'foo',value:'blah'},
  {name:'arrayOne',value: JSON.stringify(arrayOne)}
],

and in PHP:

$arrayOne = json_decode($_POST['arrayOne'], true);