17 exercises found
Discover how to move around files with lightning speed using Vim's powerful navigation commands.
Discover why each component needs crystal-clear, non-overlapping responsibilities.
See how major companies implement leader election at scale. Learn from production deployments handling millions of requests.
Leader election is powerful but not always the right choice. Understand the trade-offs, failure modes, and alternatives.
console.log() is how JavaScript talks to you — it prints any value so you can see what your code is doing.
typeof is a built-in tool that tells you the type of any value — essential for debugging and validating data.
Closures keep variables in memory long after their creator function finishes — this can cause memory leaks if not managed carefully.
Anonymous functions have no built-in name. Named function expressions give a name for debugging — but that name is only accessible inside the function itself.
Constraints are rules that protect your data. A Primary Key uniquely identifies every row. Other constraints stop bad data from ever entering the table.
A trigger fires automatically when a row is inserted, updated, or deleted — perfect for audit logs, data validation, and keeping derived values in sync.
When there is no single middle value, the median splits the difference — and that small detail trips up a lot of beginners.
When a function calls itself forever without stopping, the call stack fills up and crashes. Understanding why helps you write safer code.
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