GUIDES
A checkbox that's simply not checked never appears in the request data at all — validating it as required fails confusingly until the form explicitly sends a false/0 value when unchecked.
Angular's own *ngIf and [ngClass] are directives too — the only difference between those and a hand-written custom one is who wrote the class, not what mechanism is at work.
$_REQUEST reads from GET, POST, and cookies all at once — which sounds convenient until two of those sources happen to define the same key, and precedence quietly decides which value wins.
The core pattern is always the same three steps: intercept the action, fetch or send data with AJAX, then update the specific DOM elements that changed — no full page reload needed.
A custom class belongs in app/, autoloaded automatically by Composer's PSR-4 mapping — a global helper function needs one extra step: registering its file explicitly in composer.json.
required, min/max, email, and unique — the validation rules that cover most real forms, plus the Form Request pattern for keeping validation out of the controller.
HTML5 attributes handle the simplest cases for free — plain JavaScript and jQuery both step in for anything more specific, but neither replaces validating the same data again on the server.
Picking the wrong direction for a relationship — defining hasOne where belongsTo actually belongs — is the single most common beginner mistake, and it comes down to which table physically holds the foreign key.
Clearing existing options before appending new ones is the detail that separates a working dependent-dropdown pattern from one that silently accumulates duplicates.
The Ondřej Surý PPA is what makes running several PHP versions side by side on one Ubuntu server actually practical — Ubuntu's own default repositories only ship one PHP version at a time.
providedIn: 'root' is what makes a service a genuine singleton across the whole app — omitting it, or scoping it to a specific module or component, changes how many instances actually exist.
A working LAMP stack setup for Ubuntu — apt package installation, the Apache/MySQL services, and the one phpMyAdmin config step people usually miss.
