I am currently trying to change the map displayed on screen dependent on which anchor tag is clicked. The lat and long for is stored in an HTML attribute on the anchor tag c
As @Nell said new google.maps.LatLng constructor accepts 2 separate parameters (lat, lng) and not just single string.
What you tried to do was
new google.maps.LatLng('-30, 150')
but correct way to initialize LatLng is to pass lat and lng separately.
new google.maps.LatLng(-30, 150)
I would never store it in data attribute as single entity rather as
data-lat="53.488188"
data-lng="-2.373019"