How To Write Unmaintainable Code

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How to Write Unmaintainable Code

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Ingredient 0

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Less Lines of Code Self-Documenting Code Work with Objects My Goals 15 Years Ago

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create blog post

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☑ Photo by Stan B on Unsplash

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hmm?

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Bene fi ts we prevented lots of security issues (SQL Injection, CSRF, ...) Drawbacks "Magic" - di ff i cult to follow extensible, but not extensible

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Less Lines of Code explicit Code Self-Documenting Code Documented Code Work with Objects Immutable & Functional Patterns

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Elements of Maintainable Code

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Photo by Alexander Hafemann on Unsplash

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basically: compact is good. BUT: explicit is better than "compact". clear is better than "magic".

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Key Question: What do I need myself to understand the code in 3 years from now?

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1) Intrinsic Similarity consistent naming coherence "new code should be written the way old code was"

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2) Immutability & Pure Functions

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Immutability = state in object does not change ≈ no setters

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Bene fi ts Objects will never change easily comparable easily composable

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calculateLabel(Node) Node Pure Functions no side e ff ects deterministic (same input => same output) result a() b() c() d()

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composable functions = processing pipelines

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Recommendation: learn some functional programming fi lter, map, reduce divide-and-conquer

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3) Libraries over Frameworks your code your code lib 1 lib 2

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4) (e2e) Tests mocks only for faking external APIs

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5) Reduce Complexity

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Complexity = all parts making it di ffi cult to understand software or to change it. Root Causes of Complexity = Dependencies + Obscurity

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we want Deep Modules

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6) Document "Why"

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Dokumentation "Why" DESIGN COMMENTS ... The design comment basically states how and why a given piece of code uses certain algorithms, techniques, tricks, and implementation. It is an higher level overview of what you'll see implemented in the code. With such background, reading the code will be simpler. Moreover I tend to trust more code where I can find design notes. At least I know that some kind of explicit design phase happened, at some point, during the development process.

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Goal: Give Context Explain WHY

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every class: a Why Comment, or a link to a Why Comment.

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Sketches + Diagrams

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7) Write Concepts

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Konzepte

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Konzepte

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at a single place, f.e. at the source code (Alternative: Wiki oÄ) with Date with Author