为什么PHP json_encode展平数组？

Question

I have this PHP array ( $savedRequestDates ) of dates:

Array ( [0] => 2018-03-29 10:56:31 [1] => 2018-03-29 10:58:09 [2] => 2018-04-12 11:28:41 [3] => 2018-04-12 13:07:25 [4] => 2018-05-09 13:08:07 ) 

At the bottom of the same .php page I have this:

<script type="text/javascript">
var sessions = new Array('<?php echo json_encode($savedRequestDates); ?>');
console.log(sessions[0]);
</script>

The console.log(sessions[0]); returns:

["2018-03-29 10:56:31","2018-03-29 10:58:09","2018-04-12 11:28:41","2018-04-12 13:07:25","2018-05-09 13:08:07"]

Why is the JavaScript array flattening at the 0 index? If I try console.log(sessions); it returns an array with one variable, not 5, as the php array clearly shows.

Am I missing something here?

Answer 1

This happens because you're wrapping the array from PHP which another array ( new Array ). Just remove the new Array part and it will work fine.

var sessions = <?php echo json_encode($savedRequestDates); ?>;

Answer 2

From what I see the call to json_encode will create a full JSON object and not just the content of the array. You are enclosing the entire output of the PHP generated array as index 0 inside the new Array .

So removing the new Array will generate what you are looking for.

Try this:

<script type="text/javascript">
var sessions = <?php echo json_encode($savedRequestDates); ?>;
console.log(sessions);
</script>

And you should see the entire array.