JS sending array to php function but it gives array to string conversion error on implode

Question

I have a fairly simple axios call going on within a vue component where I'm taking an array from the data and sending it via post URL to a php class that's trying to work with it. The current issue is that when it hits the php function, I'm getting an array to string conversion error, though I feel like the structure is correct within the data object in vue.

Tne php function is:

public function testStores( array $stores = null){
  $storeTest = empty($stores)   ?  ''  : "STORES:".implode(',',$stores). ";
}

Implode isn't working here due to the array to string issue, but I would expect $storeTest to give me "5, 10" in this case. Just a comma separated string made from the IDs.

What have I done wrong?

UPDATE: I'm dumping the array now, right before I call the implode function, and this is what prints:

array:2 [
  0 => array:1 [
    "id" => "5"
  ]
  1 => array:1 [
    "id" => "10"
  ]
]

var vm = 
new Vue({
  el: "#app",
  data: {
    stores: [
      {id: "5"},
      {id: "10"}
    ]
  },
  methods: {
    getStores(){
      
      axios({
        method: 'post',
        url: test,
        data: {
          stores: this.stores
        }
      }).then(function (response) {

      }).catch(function (error) {

      });
    }
  }
  
  })

<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.17/vue.js"></script>
<div id="app">
<button @click="getNames()">TEST</button>
</div>

Do you parse the JSON stores array in PHP before using it like an array because the axios is sending a JSON string not a PHP array — Mehdi Benmoha, Feb 03 '22 at 13:40
Call `json_decode($input_from_front_end, true)` before passing it to your function. Make sure 2nd param is _true_. Read more about it here https://www.php.net/manual/en/function.json-decode — waterloomatt, Feb 03 '22 at 13:42
@waterloomatt so I could just run something like ```$newArray = json_decode($stores, true)``` and then just run implode on ```$newArray```? Thanks, I'm trying that now — Geoff_S, Feb 03 '22 at 14:33
@waterloomatt that results in an error because param 1 of json_decode() is expected to be a string, and it's given an array — Geoff_S, Feb 03 '22 at 14:34
@MehdiBenmoha apologies that I didn't add it at first, just added in an edit: I'm running json_encode in a function that sends the array into the php function where I'm trying to implode it — Geoff_S, Feb 03 '22 at 14:38
@MehdiBenmoha disregard, that's just how I'm encoding the results back to the page view. Can you check my update now? that is the array structure I'm dumping immediately before the implode function — Geoff_S, Feb 03 '22 at 14:58
@waterloomatt Can you check my update now? that is the array structure I'm dumping immediately before the implode function — Geoff_S, Feb 03 '22 at 14:58
If stores in the JS was just `stores: [5, 10]` then it'd send a simple 1D array to the server which would be easy to implode. — ADyson, Feb 03 '22 at 15:50

score 0 · Answer 1 · answered Feb 03 '22 at 15:56

You are sending a complicated structure through to the backend which you have to massage so that you can call implode on it. Here's how to massage it into a flat array.

<?php

// This is the data coming from the front end. 
$post = '{
   "stores":[
      {
         "id":"5"
      },
      {
         "id":"10"
      }
   ]
}';

// Decode it into an array
$input = json_decode($post, true);

// You now have an array that looks like this,

// Array
// (
//     [stores] => Array
//         (
//             [0] => Array
//                 (
//                     [id] => 5
//                 )
//             [1] => Array
//                 (
//                     [id] => 10
//                 )
//         )
// )

// Grab the sub-array from under `stores`.
$idList = $input['stores'];

// You now have an array that looks like this,
// Array
// (
//     [0] => Array
//         (
//             [id] => 5
//         )
//     [1] => Array
//         (
//             [id] => 10
//         )
// )


// You have to now flatten the array so that you have a single list of IDs like, [5, 10]
// You can use this, https://stackoverflow.com/a/8755001/296555
$flatArray = array_map('current', $idList);

// Now you can pass that to your function, 

function testStores( array $stores = null) {
  return empty($stores)   ?  ''  : "STORES:".implode(',',$stores);
}

echo testStores($flatArray);

As @ADyson points out, it would be better for the front end to pass a simple list to the backend. Try to get it to pass something like,

data: [5,10]

You can pass that directly to your function after json_decoding it.

Demo, http://sandbox.onlinephpfunctions.com/code/87228d49eab2db032c0e0a8549cc340314555f7d — waterloomatt, Feb 03 '22 at 15:58

JS sending array to php function but it gives array to string conversion error on implode

1 Answers1