Terms starting with "F"
Fail Fast Principle
1
Detect and report errors at the earliest possible point rather than allowing invalid state to propagate and cause confusing failures elsewhere.
6mo ago
Code Quality beginner
Fan-In / Fan-Out
Fan-in measures how many modules call a given module; fan-out measures how many modules it calls — high fan-out indicates high coupling.
6mo ago
Code Quality intermediate
Feature Envy
PHP 5.0+
1
A method that accesses the data of another class more than its own — suggesting it belongs in that other class.
6mo ago
Code Quality intermediate
Feature Flag / Feature Toggle
PHP 5.0+
1
A runtime switch that enables or disables features without deploying new code, decoupling deployment from release.
6mo ago
Code Quality beginner
Feature Toggle Types
Release toggles, ops toggles, experiment toggles, and permission toggles — each with different lifespans, owners, and removal disciplines.
6mo ago
DevOps intermediate
Fetch API & HTTP Requests
ES2015
11
The modern browser API for HTTP requests — Promise-based, streaming-capable, and replacing XMLHttpRequest in all new code.
6mo ago
JavaScript beginner
Fibers (PHP 8.1)
PHP 8.1+
4
Fibers provide cooperative concurrency primitives — lightweight coroutines that can pause and resume execution within a single thread.
6mo ago
PHP advanced
Fibers in Practice (Revolt / Amp)
PHP 8.1+
1
Using PHP 8.1 Fibers with event-loop libraries like Revolt or Amp to write non-blocking concurrent code in a synchronous, readable style.
6mo ago
PHP advanced
File Extension Bypass
PHP 5.0+
Circumventing upload filters via double extensions, null bytes, or alternate MIME types to upload executable files disguised as safe ones.
CWE-434 OWASP A4:2021
6mo ago
Security intermediate
9.8
filter_var()
PHP 5.2+
2
PHP's built-in input validation and sanitisation function supporting email, URL, IP, int, and float validators.
6mo ago
PHP beginner
Fine-Tuning LLMs
1
Training a pre-trained LLM on domain-specific data to improve performance on a specific task — more expensive and complex than prompt engineering but produces more consistent results.
6mo ago
AI / ML advanced
First Class Callable Syntax (PHP 8.1)
PHP 8.1+
Creates a Closure from any callable using func(...) syntax, replacing the verbose Closure::fromCallable() boilerplate.
6mo ago
PHP intermediate
First-Class Callable Syntax (PHP 8.1)
PHP 8.1+
PHP 8.1's Closure::fromCallable() shorthand — strlen(...) creates a Closure from any callable without verbose wrapper syntax.
6mo ago
PHP intermediate
Fixing Primitive Obsession with Value Objects
Replacing raw strings, ints, and floats representing domain concepts with dedicated Value Object classes that enforce invariants at construction.
6mo ago
Code Quality intermediate
Flaky Tests
Tests that pass and fail non-deterministically on the same code — caused by shared state, timing dependencies, external services, or random data.
6mo ago
Testing intermediate
Flame Graphs for PHP Profiling
PHP 5.0+
A visualisation of sampled call stacks showing where CPU time is spent — the fastest way to identify hot paths in a PHP application.
6mo ago
Performance intermediate
Fluent Interface / Method Chaining
PHP 5.0+
An API design style where methods return $this, enabling readable chains of calls that resemble natural language.
6mo ago
PHP intermediate
Fluent Naming for Boolean Methods
1
Prefix boolean-returning methods with is, has, can, should, or was so conditionals read as natural English sentences.
6mo ago
Style beginner
Flyweight Pattern
2
A structural pattern that shares common state between many objects rather than storing it in each instance — dramatically reducing memory for large numbers of similar objects.
6mo ago
Code Quality advanced
Focus Management
ES5 Programmatically controlling keyboard focus in SPAs and complex UIs — ensuring focus moves logically when modals open, routes change, and dynamic content loads.
6mo ago
Accessibility intermediate