<?php
$m = new MongoClient();

$res = $m->demo->poiConcat->aggregate( [
    [ '$match' => [ 'ts' => new MongoRegex( '/^cuisine=/' ) ] ],
    [ '$unwind' => '$ts' ],
    [ '$match' => [ 'ts' => new MongoRegex( '/^cuisine=/' ) ] ],
    /* Now we group on the ts, and add the count */
    [ '$group' => [ '_id' => '$ts', 'count' => [ '$sum' => 1 ] ] ],
] );

var_dump( $res['result'] );
?>