Terms starting with "E"
Entity Resolution and Deduplication
The process of identifying records that refer to the same real-world entity and merging them into a single canonical representation.
6d ago
Knowledge Engineering advanced
Euclidean Algorithm
PHP 7.1+ An ancient method for computing the greatest common divisor of two integers by repeatedly taking remainders until one becomes zero.
2w ago
Algorithms beginner
Escape Analysis
A compiler optimisation that determines whether an object's lifetime escapes its allocating scope, enabling stack allocation or full elimination of heap allocations.
3w ago
Compiler advanced
Error Recovery Patterns
Design strategies for gracefully handling failures and restoring system functionality without data loss or user disruption.
2mo 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.
3mo ago
JavaScript intermediate
each() & list() — Deprecated Iteration
PHP 3.0+
each() was deprecated in PHP 7.2 and removed in PHP 8 — replace while(list($k,$v)=each($arr)) with foreach. list() itself is still valid as [] destructuring.
3mo ago
PHP beginner
Elasticsearch Fundamentals
PHP 7.0+
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.
3mo 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.
3mo 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).
3mo ago
PHP intermediate
ereg() / eregi() — POSIX Regex Removed in PHP 7
PHP 3.0+
ereg() and eregi() were POSIX regex functions removed in PHP 7.0 — replace with preg_match() (PCRE) which is faster, more powerful, and the standard since PHP 4.
3mo ago
PHP beginner
Error Budget
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.
3mo ago
Observability intermediate
Error Logging
PHP 4.0+
2
Recording application errors, exceptions, and diagnostic information to persistent storage — essential for diagnosing production issues where display_errors must be off and errors are invisible to users.
3mo ago
PHP beginner
Error Reporting & Display
PHP 4.0+
1
PHP's error_reporting level and display_errors directive control which errors are shown and where — development needs E_ALL with display on; production needs E_ALL with display off and logging on.
3mo ago
PHP beginner
Error.cause — Error Chaining
ES2022
2
ES2022 added a cause option to the Error constructor — 'new Error('message', { cause: originalError })' — enabling proper error chaining where a high-level error wraps its underlying cause, preserving the full error context across abstraction layers.
3mo ago
JavaScript beginner
Event Sourcing vs Messaging
1
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.
3mo 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.
3mo 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.
3mo ago
JavaScript intermediate
Exactly-Once Delivery
4
Exactly-once delivery ensures each message is processed exactly once — achievable only with coordination between broker and consumer using transactions or idempotent producers.
3mo ago
Messaging advanced
Exception Handling Introduced (PHP 5)
PHP 5.0+
PHP 5 introduced try/catch/finally and the Exception class — replacing PHP 4's procedural error handling with structured exception-based patterns.
3mo ago
PHP beginner
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.
3mo ago
TypeScript intermediate