Technical Practices for Sustainable Code - Chicago Code Camp 2019

@TheQuinnGil https://QuinnGil.com with Technical Practices for Sustainable Code Feature Parity
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@TheQuinnGil https://QuinnGil.com Technical Practices for Sustainable Code

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@TheQuinnGil https://QuinnGil.com Sustainable Code

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@TheQuinnGil https://QuinnGil.com What’s Our Job? Sustainable Code - Why?

@TheQuinnGil https://QuinnGil.com Sustainably grow the value of the company’s digital
assets. Sustainable Code - What’s our job?

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@TheQuinnGil https://QuinnGil.com Mindset Change Sustainable Code - How?

@TheQuinnGil https://QuinnGil.com Technical Practices Sustainable Code - How?

@TheQuinnGil https://QuinnGil.com Sustainable Code through Technical Practices

@TheQuinnGil https://QuinnGil.com Sustainable Code through Technical Practices • No Getters
/ No Setters • `if` Only As Guard Clause • Isolate Their Code • Never `null` • Limit Object Creation • Composition, Not Inheritance • <Strong opinions loosely held> • Be Immutable • No Primitives • Extract Cohesion • No Public Statics • Never Reflection

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@TheQuinnGil https://QuinnGil.com Fully Test Behaviors Sustainable Code - Testing!

@TheQuinnGil https://QuinnGil.com No Getters / No Setters Technical Practices

@TheQuinnGil https://QuinnGil.com Technical Practices - No Getters / No Setters
class FizzBuzzBag{ public int Input{ get; set; } public string Result{ get; set; } } class FizzBuzzBag: def __init__(self): self._result = None self._input = None @property def result(self): return self._result @result.setter def result(self, value): self._result = value @property def input(self): return self._input @input.setter def input(self, value): self._input = value class FizzBuzzBag{ private int input; private String result; public String getResult(){ return result; } public void setResult(String value){ result = value; } public int getInput(){ return input; } public void setInput(int value){ input = value; } } class FizzBuzzBag attr_accessor :input attr_accessor :result end

No Way

@TheQuinnGil https://QuinnGil.com Technical Practices - No Getters Why?

@TheQuinnGil https://QuinnGil.com Technical Practices - No Setters Why?

How?

@TheQuinnGil https://QuinnGil.com No Getters / No Setters - How? The
Class Does It

public class FizzBuzz{ public int Input { get; set; } public string Result { get; set; } } public static class FizzBuzzUtils{ public static void Calculate(FizzBuzz fb){ if (fb.Input % 3 == 0){ fb.Result = "Fizz"; } if (fb.Input % 5 == 0){ if (fb.Result == null){ fb.Result = "Buzz"; } else { fb.Result += "Buzz"; } } if (string.IsNullOrEmpty(fb.Result)){ fb.Result = fb.Input.ToString(); } } }

public class FizzBuzz{ private readonly int _input; public FizzBuzz(int input) => _input = input; public string Result(){ string result = null; if (_input % 3 == 0) result = "Fizz"; if (_input % 5 == 0){ if (result == null) result = "Buzz"; else result += "Buzz"; } if (string.IsNullOrEmpty(result)){ result = _input.ToString(); } return result; } } public class FizzBuzz{ public int Input { get; set; } public string Result { get; set; } } public static class FizzBuzzUtils{ public static void Calculate(FizzBuzz fb){ if (fb.Input % 3 == 0){ fb.Result = "Fizz"; } if (fb.Input % 5 == 0){ if (fb.Result == null){ fb.Result = "Buzz"; } else { fb.Result += "Buzz"; } } if (string.IsNullOrEmpty(fb.Result)){ fb.Result = fb.Input.ToString(); } } }

@TheQuinnGil https://QuinnGil.com Technical Practices - No Setters Benefits

@TheQuinnGil https://QuinnGil.com `if` Only As Guard Clause Technical Practices

@TheQuinnGil https://QuinnGil.com Technical Practices - `if` Only As Guard Clause
No Way

Success Path

@TheQuinnGil https://QuinnGil.com `if` Only As Guard Clause - Success Path
public class FizzBuzz{ private readonly int _input; public FizzBuzz(int input) => _input = input; public string Result(){ string result = null; if (_input % 3 == 0) result = "Fizz"; if (_input % 5 == 0){ if (result == null) result = "Buzz"; else result += "Buzz"; } if (string.IsNullOrEmpty(result)){ result = _input.ToString(); } return result; } }

@TheQuinnGil https://QuinnGil.com `if` Only As Guard Clause - Success Path
public class FizzBuzz{ public string Result(){ if (_input % 15 == 0) return "FizzBuzz"; if (_input % 3 == 0) return "Fizz"; if (_input % 5 == 0) return "Buzz"; return _input.ToString(); } } public class FizzBuzz{ private readonly int _input; public FizzBuzz(int input) => _input = input; public string Result(){ string result = null; if (_input % 3 == 0) result = "Fizz"; if (_input % 5 == 0){ if (result == null) result = "Buzz"; else result += "Buzz"; } if (string.IsNullOrEmpty(result)){ result = _input.ToString(); } return result; } }

Cascading Changes

How?

public class FizzBuzz{ public string Result(){ if (_input % 15 == 0) return "FizzBuzz"; if (_input % 3 == 0) return "Fizz"; if (_input % 5 == 0) return "Buzz"; return _input.ToString(); } }

public class FizzBuzz{ public string Result(){ if (_input % 15 == 0) return "FizzBuzz"; if (_input % 3 == 0) return "Fizz"; if (_input % 5 == 0) return "Buzz"; return _input.ToString(); } } public class FizzBuzz{ public string Result(){ if (IsFizzBuzz()) return "FizzBuzz"; if (IsFizz()) return "Fizz"; if (IsBuzz()) return "Buzz"; return InputToString(); } }

@TheQuinnGil https://QuinnGil.com `if` Only As Guard Clause Technical Practices

@TheQuinnGil https://QuinnGil.com Isolate Their Code Technical Practices

@TheQuinnGil https://QuinnGil.com Technical Practices - Isolate Their Code - 3rd
Party public class FizzBuzz{ private readonly string _input; public FizzBuzz(string input) => _input = input; public string Result(){ JObject jObject = JObject.Parse(_input); int input = jObject.Value<int>("number"); if (IsFizzBuzz(input)) return "FizzBuzz"; if (IsFizz(input)) return "Fizz"; if (IsBuzz(input)) return "Buzz"; return input.ToString(); } }

@TheQuinnGil https://QuinnGil.com Technical Practices - Isolate Their Code - 3rd
Party public class FizzBuzz{ private readonly string _input; private readonly IParser _parser; public FizzBuzz(string input) => _input = input; public string Result(){ IParsedObject pObject = _parser.Parse(_input); int input = pObject.IntValue("input"); if (IsFizzBuzz(input)) return "FizzBuzz"; if (IsFizz(input)) return "Fizz"; if (IsBuzz(input)) return "Buzz"; return input.ToString(); } }

@TheQuinnGil https://QuinnGil.com Operating System Technical Practices - Isolate Their Code

@TheQuinnGil https://QuinnGil.com How? Technical Practices - Isolate Their Code

@TheQuinnGil https://QuinnGil.com Technical Practices - Isolate Their Code - How?
internal class HttpClientBookEnd : IHttpClientBookEnd{ private static HttpClient _testClient; #if DEBUG public static void SetTestClient(HttpClient testClient) => _testClient = testClient; #endif private readonly HttpClient _httpClient; public HttpClientBookEnd() : this(new HttpClient()){} private HttpClientBookEnd(HttpClient httpClient) => _httpClient = httpClient; public void SendRequestAsync(HttpRequestMessage msg) => HttpClient().SendAsync(msg); private HttpClient HttpClient() => _testClient ?? _httpClient; }

@TheQuinnGil https://QuinnGil.com User Interface Technical Practices - Isolate Their Code

@TheQuinnGil https://QuinnGil.com Never `null` Technical Practices

@TheQuinnGil https://QuinnGil.com Why? Technical Practices - Never `null`

@TheQuinnGil https://QuinnGil.com How? Technical Practices - Never `null`

@TheQuinnGil https://QuinnGil.com Technical Practices - Never `null` public string CalculateThing(ICanBeNull
canBeNull) { if (canBeNull == null) return "Default"; IAlsoNull alsoNull = canBeNull.Example(); if (alsoNull == null) return "Default"; string sample = alsoNull.Sample(); if (sample == null) return "Default"; return sample; }

@TheQuinnGil https://QuinnGil.com Technical Practices - Never `null` public string CalculateThing(ICanNotBeNull
canNotBeNull) { return canNotBeNull.Example().Sample(); } public string CalculateThing(ICanBeNull canBeNull) { if (canBeNull == null) return "Default"; IAlsoNull alsoNull = canBeNull.Example(); if (alsoNull == null) return "Default"; string sample = alsoNull.Sample(); if (sample == null) return "Default"; return sample; }

canBeNull) { if (canBeNull == null) return "Default"; IAlsoNull alsoNull = canBeNull.Example(); if (alsoNull == null) return "Default"; string sample = alsoNull.Sample(); if (sample == null) return "Default"; return sample; } public string CalculateThing(ICanNotBeNull canNotBeNull) { return canNotBeNull.Example().Sample(); } public void Foo(){ string thing = _bar.CalculateThing(_canBeNull); //Do something with `thing` }

canBeNull) { if (canBeNull == null) return "Default"; IAlsoNull alsoNull = canBeNull.Example(); if (alsoNull == null) return "Default"; string sample = alsoNull.Sample(); if (sample == null) return "Default"; return sample; } public string CalculateThing(ICanNotBeNull canNotBeNull) { return canNotBeNull.Example().Sample(); } public void Foo(){ string thing = _bar.CalculateThing(_canBeNull); //Do something with `thing` } public void Foo(){ string thing = _canNotBeNull.Example().Sample(); //Do something with `thing` }

canBeNull) { if (canBeNull == null) return "Default"; IAlsoNull alsoNull = canBeNull.Example(); if (alsoNull == null) return "Default"; string sample = alsoNull.Sample(); if (sample == null) return "Default"; return sample; } public string CalculateThing(ICanNotBeNull canNotBeNull) { return canNotBeNull.Example().Sample(); } public class NullObject : ICanNotBeNull{ public IAlsoNotNull Example() => new NullObjectAlso(); } public class NullObjectAlso : IAlsoNotNull{ public string Sample() => "Default"; }

@TheQuinnGil https://QuinnGil.com Languages and Null

@TheQuinnGil https://QuinnGil.com Never `null` Technical Practices

@TheQuinnGil https://QuinnGil.com THANK YOU!

Technical Practices for Sustainable Code - Chic...

Technical Practices for Sustainable Code - Chicago Code Camp 2019

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