Jesse's Notes

ENOF - Easiest Nearest Owwie First

2 min read

ENOF (Easiest Nearest Owwie First) is a refactoring technique for working with code you don’t fully understand, named by GeePaw Hill.

Core Concept

Narrow your focus until you find something you can understand, but that takes a reading or two to grasp - it’s graspable, but not readily graspable. Fix that. Then repeat.

Three Things to Look For

1. Local Variables Named Poorly

Variables named in a way that obscures their intention.

// Before
int x = customer.GetOrders().Count();
 
// After - reveals intention
int orderCount = customer.GetOrders().Count();

2. Declaration Without Initialization

Places where a variable is declared, but not initialized.

// Before - clue to extractable method
string message;
if (isError)
{
    message = "Error occurred";
}
else
{
    message = "Success";
}

This is a strong clue that the if statement is an extractable method:

// After
string message = DetermineMessage(isError);
 
private string DetermineMessage(bool isError)
{
    return isError ? "Error occurred" : "Success";
}

3. Early Return Opportunities

Ways to “undent” - reduce nesting by getting out of a method with at least one case completely dealt with.

// Before - deeply nested
public void ProcessOrder(Order order)
{
    if (order != null)
    {
        if (order.IsValid())
        {
            if (order.Customer.IsActive())
            {
                // actual logic here
            }
        }
    }
}
 
// After - guard clauses
public void ProcessOrder(Order order)
{
    if (order == null) return;
    if (!order.IsValid()) return;
    if (!order.Customer.IsActive()) return;
 
    // actual logic here - less indented, easier to read
}

Benefits of ENOF

By following this method, two things occur:

  1. Modest Understanding: You gain some understanding of the high-level behavior of the code
  2. Emergent Design: Each pass yields new results, and you start to develop a view of the big picture refactor you want to work towards

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