Save results from pdo query to a javascript variable

Question

I am new to javascript so please be patient with me. I have a function in php which goes like this:

 public function getSubjects() {
            $stmt = $this->_db->prepare('SELECT id, subject from subjects');
            $stmt->execute();                     
            return  $stmt->fetchall();
        }

Then I have a variable subs in javascript which is hardocded like this:

var subs = {"Maths":1,"Geography":2,"Chmesitry":3,"Literature":4};

How do I populate the subs variable with the format above from the getSubjects method?

Answer 1

I like to use json_encode to convert the array to json so it can be used as an array of objects in JS.

PHP:

public function getSubjects() {
    $stmt = $this->_db->prepare('SELECT id, subject from subjects');
    $stmt->execute();                     
    return json_encode($stmt->fetchall());
}

In javascript:

var subs = <?php echo getSubjects(); ?>;
console.log(subs);