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We're now going to talk about
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the consolidate conditional expression refactoring.
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A common situation in code is that you have a set
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of conditionals with the same result. What that means that
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sometimes the code contains a series of conditional checks in which
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each check is different, yet the resulting action is the
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same. In these cases, the code could be improved by combining
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the conditionals using, for example, and, and or, as connectors. So
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as to have a single conditional check, with a single result.
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At that point you can also extract those conditional into a
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method. And replace the conditional with a call, to debt matter consolidating
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the conditional code in this way can make the checks clearer
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by showing that you're really making a single check rather than multiple
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checks, and extracted that condition and having that matter instead of
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a condition can clarify your code by explaining why you're doing a
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given check, rather than how you're doing it. You can see an
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example of that situation in this code, which is the disabilityAmount method.
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As the name of the method says, the purpose of this code
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is to compute the disability amount for a given, for example, employee.
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And there is a set of initial checks in the methods whose
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goal is to decide whether there's this disabilityAmount should be instead zero.
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And as you can see, there's multiple conditions. For example, there's a
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check about the seniority level, and about the number of months that
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the employee's been disabled. So far, whether the employee is part time
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and the outcome of all these check is always the same. If they're
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true, if the check is satisfied then there is no disability
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amount. So the disabilityAmount is zero. So what I will do
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if I apply the consolidate conditional expression to this matter, is
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that I will take these three conditionals. I will put them together
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by saying basically that if seniority is less than 2 or
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monthsDisabled is greater than 12 or isPartTime is true then the
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return should be zero. And once I have this combined conditional,
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as I see here, I will just extract that into a method.
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