When should you code FAIL FAST? 🔥 #ARCHITECTURE #FOCUS 🔥 What FAIL FAST is ❌NOT❌? 💥 #javascript’s NaN: ‘hi mom’ * 5... 💥 why does a platform perform a stupid operation? 💥 why doesn’t it EXPLICITLY notify the developer (by throwing an error)? FAIL FAST is: 🥊 a design technique (or coding style) 🥊 similar to “strong typing” where: 🥊 if something MIGHT be incorrect, it FAILs explicitly 🥊 you check your state along as the logic is performed 🥊 as soon as possible 🥊 so that we don’t carry on with an INVALID situation 🥊 and we DON’T WORK AROUND the problem instead of solving it 🧟 same as with mutation testing: kill the mutants! 🧟🧟🧟 🪓 if something doesn’t make sense -> BREAK IT! 🪓 CONSEQUENCES? 🪚 your codebase would throw way more errors 🐛 🪚 you’d have to handle them 👷‍♂️ 🪚 … but you also GET RID OF all invalid/inconsistent states 💪 BTW 🟥FAILING BUILDS 🟥 adapt the 🟥 FAIL FAST 🟥 strategy 🟥 Even if the linter raises an error, you shall not be able to deploy. Examples of FAIL-FAST: 💣 DON’T ALLOW to create an invalid/inconsistent object 💊 FIX: conditionally throw an error in your constructor, if any data/logic is inconsistent. 💣 if you expect something and don’t get it, FAIL FAST by throwing an error 💊 FIX: #typescript assertion function 💣 Don't rescue your logic by introducing meaningless defaults like #javascript/#typescript “?? []” - WHY IS THE ARRAY NOT THERE IN THE FIRST PLACE? 💊 FIX: if you want an array to be guaranteed somewhere… then f🤬🤬🤬ing GUARANTEE IT 😅 💣 AVOID OPTIONAL PROPERTIES as much as possible. Optional properties multiply number of potential states, where majority of them is usually invalid. 💊 FIX: Introduce a #typescript union instead. 🤮 sidenote: leaky data structures are the worst… 🤮 There’s plenty of space to apply FAIL FAST techniques within your #angular, #react and #vue applications. Just don’t let any doubtful state leak into your logic. See examples below: