GUIDES
*ngFor only iterates arrays and other iterables natively — looping over a plain object's keys and values needs either the built-in KeyValue pipe or converting the object first.
php artisan make:component, passing data as props, and the difference between a class-backed component and an anonymous view-only one.
A raw query is only as safe as its parameter binding — concatenating a variable directly into a raw string reopens the exact SQL injection risk Eloquent otherwise protects against automatically.
A pipe transforms a value for display, right in the template, without touching the underlying data — the built-in set covers formatting basics, and a custom pipe extends the same pattern to anything else.
Any operation touching more than one table — where a partial failure would leave the data in a genuinely inconsistent state — belongs inside a transaction, not left to run as separate, independent queries.
The multiple attribute on a file input is the easy part — looping through the resulting FileList and appending each file to FormData under a repeated key is what a backend actually needs to receive them all.
The confirmed rule has one specific, easy-to-miss requirement: the confirmation field must be named exactly {field}_confirmation, or the rule silently never matches anything.
Define the output grain first, filter source rows with WHERE, aggregate with GROUP BY, and use HAVING for conditions on grouped or aggregate results.
The native Constraint Validation API — setCustomValidity() specifically — lets a browser show its own built-in validation message for a custom check like password matching, without a framework.
whereIn, whereNull, orWhere, and a handful of siblings cover almost every filtering need — the one that actually causes bugs is orWhere's grouping behavior when mixed with other conditions.
Two genuinely different approaches exist — rendering the DOM to an image-based PDF entirely in the browser, or asking a server to generate a real, selectable-text PDF — and they aren't interchangeable.
A search or filter form where every field is optional usually ends up as a wall of if statements around a query — when() folds each one into a single fluent chain instead.
