reaction_url.js

var reactionImageUrls = {'angry': 'http://url.com/', 'wow': 'http://url.com/'};

firebase.database().ref('Points').once('value', function(points) {
  points.forEach(function(point) {
    var location = data.val().Location;
    var reaction = data.val().Reaction;
                         
    imageUrl = reactionImageUrls[reaction];
    
    // display a point
  })
});

sample_data.yml

users:
  user_1:
    current_location:
      long: 12.345
       lat: 12.345
    points:
      - 'point_1'
      - 'point_2'
  user_2:
      - 'point_3'
  user_3:
      - 'point_4'
points:
  point_1:
    user_id: 'user_1'
    reaction: 'sad'
    state: 'private'
    location:
      long: 12.345
       lat: 12.345
    time: 1528191174489
  point_2:
    ...
  point_3:
    ...
  point_4:
    ...
reactions:
  sad:
    ...
  joy:
    ...
  angry:
    ...

SQL Join

id	value	home_page
1	'a'	'google'
2	'b'	'yahoo'

home_page	url
'google'	'http://google.com/'
'yahoo'	'http://yahoo.com'