javascript
The Singleton pattern in JavaScript ensures one shared instance with a global access point. A practical implementation using an object literal and Object.freeze, a shared bucket example, and where a singleton fits: configuration, logging, or a central data store.
ruby
cattr_accessor, mattr_accessor, and the thread_cattr and thread_mattr variants explained: ActiveSupport helpers for class-level and module-level attributes, plus thread-safe versions that avoid data inconsistencies in multi-threaded apps. Examples for each accessor, reader, and writer.
extend
Extend, prepend, and include in Ruby each add module code to a class differently: prepend puts the module before the class so its methods win, extend adds class methods, include adds instance methods. Short runnable examples show how each changes the method lookup chain.
Blocks, procs, and lambdas in Ruby all wrap code you can pass around, but they differ in how they check arguments and handle return. Implicit and explicit blocks with yield, building reusable procs, and when a lambda is the safer pick, all shown with runnable examples.
class_eval, instance_eval, and instance_exec power Ruby metaprogramming: reopening classes, running blocks inside an object, and passing arguments in. All explained through one MyWebServer class with a configure DSL, ending in a reusable AppConfig settings pattern.
TypeScript function generators can pause and resume execution, returning values one at a time instead of all at once. What generators are, how yield works in a simple example, and a practical number sum generator that shows where they beat regular functions.
Ruby hash destructuring can feel as smooth as JavaScript: the rightward pattern matching syntax extracts values from a hash in one line, renames them, destructures arrays, groups elements, and rebuilds hashes afterwards. Practical examples for cleaner Ruby code.
Pattern matching in Ruby turns case statements into a precise switch over data shapes: match and destructure hashes from an API response, combine several patterns in one branch, capture values across patterns, and validate configuration. Ruby 2.7+ syntax examples.
Slow test suites usually hide a few expensive tests. Minitest and RSpec both ship a built-in profiler: bin/rails test --profile and rspec --profile 10 list your slowest examples with execution times, so you know exactly which tests to optimize first.
Infinite scroll in React gets much easier with react-query: the useInfiniteQuery hook fetches posts page by page, cancels stale requests with AbortSignal, and exposes fetchNextPage for loading more. A complete typed example wrapped in a reusable usePosts hook.
Monkey patching in Ruby without global damage: why reopening a class like DateTime directly backfires, how prepend and include change the ancestor chain safely, and how refine limits your patch to a single scope so the rest of the codebase stays untouched.
Monolith, microservices, or serverless? A side by side comparison of how each backend architecture handles scaling, development speed, deployment, and cost, where each one breaks down in practice, and a summary that helps you pick the right fit for your project.
XML support in Grape API takes two steps: register the additional content_type so endpoints accept and return application/xml, then change the root element name of the XML output. Complete Ruby examples built around a products endpoint you can adapt to your API.
Running shell commands from Ruby: system, backticks, exec, the IO class, spawn, and Open3.popen3 compared with pros and cons, from quick one-liners to capturing stdout, stderr, and exit status, so you can pick the right method for scripts and production code.
Database pagination goes beyond LIMIT and OFFSET: ROW_NUMBER(), the FETCH clause, and keyset pagination each behave differently as tables grow. SQL examples for every approach, why offsets get slow on big datasets, and a verdict on which method scales best.
Database sharding in Rails step by step: create a separate database per shard, wire them up in database.yml, and query across them. Plus how sharding differs from partitioning, with a native PostgreSQL partitioning example done through Rails migrations.
Sidekiq basic_fetch vs super_fetch: open source Sidekiq fetches jobs with BRPOP and loses them when a process crashes, while Sidekiq Pro's super_fetch uses RPOPLPUSH with private per-process queues to recover orphaned jobs. What that means for queue reliability.
Generic types in TypeScript let one function, class, or interface work safely with many data types. What generics are, how a type parameter beats hardcoding a concrete entity type in a validation helper, and honest pros and cons before you use them everywhere.
Domain Driven Design in Ruby with a working example: aggregates, entities, value objects, and repositories built around a ProductCatalog, then extended with event-driven design and event sourcing, where projections rebuild state from events instead of a database.
Rails locking strategies for concurrent updates: optimistic locking with a lock_version column that works out of the box, pessimistic locking with lock! and with_lock, and practical ways to rescue and resolve the StaleObjectError that optimistic locking raises.
Rails eager_load, includes, preload, and joins each fight slow queries differently: LEFT OUTER JOIN versus separate queries, how includes picks its strategy, and when a plain joins is enough. Clear examples showing which loading method to choose for each situation.
TypeScript enums generate extra JavaScript at compile time and numeric enums are not even type-safe. Why enums can hurt bundle size and correctness, and two safer alternatives: assigning explicit string values or replacing enums with plain objects.
Ruby has four ways to load code and each behaves differently: load re-executes a file every time, autoload waits until first use, require loads once from the load path, require_relative resolves from the current file. Examples plus a summary of when to use each.