Intermediate terms
Error Recovery Patterns
Design strategies for gracefully handling failures and restoring system functionality without data loss or user disruption.
5mo ago
General intermediate
ES Modules (ESM)
ES2015
The official JavaScript module system — import and export statements enable static dependency graphs, tree-shaking, and native browser module loading without a bundler.
6mo ago
JavaScript intermediate
Elasticsearch Fundamentals
PHP 7.0+
1
A distributed search and analytics engine built on Lucene — storing documents as JSON, indexing them automatically, and providing a REST API for full-text search, aggregations, and real-time analytics.
6mo ago
Search intermediate
Engine Exceptions — Error Hierarchy (PHP 7.0)
PHP 7.0+
PHP 7.0 made fatal engine errors catchable as Error subclasses — TypeError, ParseError, ArithmeticError, DivisionByZeroError — via the shared Throwable interface.
6mo ago
PHP intermediate
Enums — First-Class Enumerations (PHP 8.1)
PHP 8.1+
PHP 8.1 native enums replace class constant hacks — providing type-safe, enumerable, matchable values with optional backing values (: string or : int).
6mo ago
PHP intermediate
Error Budget
2
Error budget is the allowed amount of unreliability within an SLO period — 99.9% SLO = 43.8 min/month downtime allowed. When budget is exhausted, reliability takes priority over features.
6mo ago
Observability intermediate
Event Sourcing vs Messaging
2
Event sourcing stores all state changes as immutable events (the source of truth) — messaging delivers events between services. They complement each other but serve different purposes.
6mo ago
Messaging intermediate
Event-Driven Concurrency
1
Event-driven concurrency uses a single-threaded event loop to handle many concurrent I/O operations — no threads, no locks, but requires non-blocking code throughout.
6mo ago
Concurrency intermediate
EventSource API — Server-Sent Events (Client Side)
HTML5
EventSource is the browser API for consuming Server-Sent Events (SSE) — a one-directional server-to-client stream over HTTP that automatically reconnects, ideal for live feeds, notifications, and streaming LLM responses.
6mo ago
JavaScript intermediate
Exhaustive Checks with never
Using the 'never' type in a default branch to make TypeScript error at compile time if a union type is not fully handled — ensures every new variant of a type forces a matching handler to be written.
6mo ago
TypeScript intermediate
Extract Class Refactoring
Extract Class splits a large class into two — moving a cohesive subset of fields and methods into a new class that the original delegates to.
6mo ago
Code Quality intermediate
Enum::cases() & Enum from()/tryFrom()
PHP 8.1+
Backed enums provide from() (throws on miss) and tryFrom() (returns null) for value lookup, plus cases() to get all cases — essential for forms and validation.
6mo ago
PHP intermediate
Enums Implementing Interfaces
PHP 8.1+
PHP 8.1 enums can implement interfaces, allowing them to be used wherever an interface is expected — enabling polymorphic enum-based dispatch.
6mo ago
PHP intermediate
Event Loop Blocking — Long Tasks
ES5
JavaScript is single-threaded — synchronous code that runs >50ms blocks the event loop, freezing UI and delaying I/O callbacks. Break long tasks into chunks.
6mo ago
JavaScript intermediate
Exception Hierarchy (Throwable, Error, Exception)
PHP 7.0+
1
PHP 7+ unified exceptions and fatal errors under the Throwable interface — catch Throwable to handle both Error and Exception in one block.
6mo ago
PHP intermediate
extract() Security Risk
PHP 4.0+
extract() creates variables from an array in the current scope — using it on user input ($_POST, $_GET) allows attackers to overwrite any local variable.
6mo ago
Security intermediate
ES6 Class Syntax
ES2015
ES6 classes are syntactic sugar over prototypal inheritance — the keywords mirror PHP but the underlying mechanism is different.
6mo ago
JavaScript intermediate
Encryption in Transit
1
Encrypting data moving between systems using TLS — protecting against interception, tampering, and man-in-the-middle attacks on all network communication.
6mo ago
Cryptography intermediate
Environment Variables
PHP 5.0+
1
Key-value pairs inherited by child processes — the standard way to pass configuration, credentials, and runtime settings to PHP applications without hardcoding.
6mo ago
Linux intermediate
Event Bus Patterns
PHP 7.0+
Patterns for routing events between publishers and subscribers — in-process event buses (Symfony EventDispatcher), message broker buses (RabbitMQ, Kafka), and hybrid architectures.
6mo ago
Messaging intermediate