Gladear

Gladear

Clarification about `assign/2,3` usage in `render/1` callbacks

I think I remember reading somewhere that calling `assign/2,3` in the `render/1` callback of a LiveView or a LiveComponent is bad practice, but I don’t recall where, nor why.

Here’s an example, for sake of clarity:

def render(assigns) do
  assigns = assign(assigns, :new_assign, assign.a1 + assigns.a2)

  ~H"""
  {@new_assign}
  """
end

Is this pattern safe? If not, why not? Is this documented somewhere in LiveView’s documentation?

Thanks in advance

Marked As Solved

LostKobrakai

LostKobrakai

This is fine, besides the fact that it runs each time render/1 is called. So do not put expensive calculations there, but otherwise this is no different to doing the same in any downstream function components.

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