I’ve a data source that’s returning some time series data that I’d like to ultimately chart in Phoenix. However I’m having some trouble massaging it into some format or another that I can use.

What I’m starting with is along the lines of:

[
  %{x: 1570117280000, y: 16},
  %{x: 1570117288000, y: 16},
  %{x: 1570117296000, y: 16},
  %{x: 1570117304000, y: 16}
]

I’ve been able to render a graph by doing:

stats
|> Enum.map(&Map.to_list/1)
|> Enum.map(&Keyword.values/1)
|> Jason.encode!()

And then passing it through the controller to the template, which gives me:

[  
  [1570117280000, 16],
  [1570117288000, 16],
  [1570117296000, 16],
  [1570117304000, 16]
]

But I’m struggling with how to format the key values. For example, converting the unix timestamp x to something more friendly.

How do I manipulate a specific key’s value when I’m going through the list?