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#php
#kotlin
#bash
#go
#sql
#rust
#typescript
#html
#java
#python
#files
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#http
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#security
#types
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#database
#dates
#format
TypeScript
const Assertions for Literal Types
`as const` freezes a value as deeply readonly and infers the narrowest possible literal types. Replaces enums for most use cases — better tree-shaking, no runtime cost.
@admin
HTML
Visually Hidden Utility (.sr-only)
Hides content from sighted users but keeps it discoverable by screen readers. Use for icon-only buttons, table-row context, and form-status announcements that don't need visible text.
SQL
GROUP BY — Aggregation Basics
`GROUP BY` collapses rows into buckets; the SELECT list must be aggregates OR grouped columns. The most common reporting pattern in SQL.
HTML
Product Page with Schema.org Markup
Marking up a product page with the Schema.org `Product` type unlocks Google's rich snippets — price, rating, availability appear directly in search results. JSON-LD is the recommended format.
TypeScript
useFetch — Minimal Data Fetching Hook
A tiny self-contained data-fetching hook with loading/error/data states and AbortController cleanup on unmount. Good baseline before reaching for TanStack Query.
Kotlin
ViewModel + StateFlow + Compose
Standard Android pattern: ViewModel holds state in a `StateFlow`, Compose collects it as state. Survives config changes; isolates business logic from UI.
Kotlin
groupBy and partition
`groupBy` returns a `Map<Key, List<T>>` keyed by what the lambda returns. `partition` is a special-case `groupBy` for booleans — returns `(matching, nonMatching)` Pair.
Kotlin
Enums with Properties and Methods
Kotlin enums can carry constructor properties and define methods — including abstract methods overridden per constant. Way more expressive than Java enums.
TypeScript
Conditional Types Basics
`T extends U ? X : Y` lets types branch on shape. Combine with `infer` to extract pieces of complex types — the building block under `ReturnType`, `Parameters`, and most utility libraries.
Bash
Rotate Logs Manually
If a service doesn't hook into logrotate, you can still rotate a log file yourself in one safe pattern: rename current → .1, truncate the original, signal the process to re-open if needed.
Bash
Squash Last N Commits
Combine the last N commits into one before merging a feature branch. Avoids hours of "WIP" / "fix typo" commits cluttering history.
Kotlin
Parameterized Tests with JUnit 5
JUnit 5 + Kotlin: `@ParameterizedTest` runs the same test body with multiple input rows. `@CsvSource` for inline data, `@MethodSource` for complex args.
SQL
Foreign Keys + ON DELETE Behavior
A foreign key prevents orphan rows. The `ON DELETE` clause decides what happens to children when the parent goes away: `CASCADE`, `SET NULL`, `RESTRICT`, `NO ACTION`.
TypeScript
Result / Either Type
Encode "this might fail" in the type signature instead of throwing. Force the caller to handle both branches at compile time. Better than try/catch for foreseeable failures.
HTML
Main Content + Aside Sidebar
`<main>` wraps the unique-to-this-page content (screen readers jump to it with a keyboard shortcut). `<aside>` is supporting / tangential content — sidebars, callouts, related links.
TypeScript
Mapped Types (Partial/Required/etc)
Mapped types iterate over keys to produce new types. The standard library's `Partial`, `Required`, `Readonly`, `Pick`, `Omit`, `Record` are all one-liners — and you can build your own.
PHP
Minimal PSR-3 Logger
A 30-line PSR-3 compatible logger you can drop into any project that expects \Psr\Log\LoggerInterface. Writes to a file using the JSON structured format.