Keeping State With Elixir Agents

The Elixir Agent module provides a simple way to store and retrieve the state in our application. Let’s see how easy it is to manage the state with an Agent process, by executing the following commands in sequence in the iex shell:

iex> {:ok, buffer} = Agent.start_link fn -> [] end 
# Output: {:ok, #PID<0.130.0>}
iex> Agent.get(buffer, fn state -> state end) 
# Output: []
iex> Agent.update(buffer, &["<h2>Hello</h2>" | &1]) 
# Output: :ok
iex> Agent.get(buffer, &(&1)) 
# Output: ["<h2>Hello</h2>"]
iex> for i <- 1..3, do: Agent.update(buffer, &["<td><#{i}</td>" | &1]) 
# Output: [:ok, :ok, :ok]
iex> Agent.get(buffer, &(&1))
# Output: ["<td><3</td>", "<td><2</td>", "<td><1</td>", "<h2>Hello</h2>"]

The use of Agent module:

The Agent module has a small API, which focuses on providing quick access to the state. In the example given above, we started an Agent with an initial state of []. Next, we ...