Tags
#php
#kotlin
#bash
#go
#sql
#rust
#typescript
#html
#java
#python
#files
#utils
#strings
#http
#concurrency
#async
#json
#arrays
#security
#types
#crypto
#database
#dates
#format
Kotlin
lazy — Lazily Computed val
`by lazy { ... }` runs the block on first access, caches the result. Default mode is thread-safe (synchronized). Perfect for expensive initialization where you might never need the value.
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JavaScript
Random Hex Color
Generates a random 6-digit hex colour string. Useful for seeding avatar backgrounds, chart series colours, placeholder UI elements, and testing colour-dependent components. The crypto version produces a more unpredictable result suitable for generating unique palette tokens.
JavaScript
Promise All with Concurrency Limit
Runs an array of async tasks with a maximum concurrency cap, preventing you from firing hundreds of requests simultaneously. Processes items in batches, moving to the next as slots free up. Essential when hitting rate-limited APIs or processing large datasets without overwhelming the server.
TypeScript
Environment Variable Validator
Validate process.env at boot-time and exit fast if anything's missing. The returned object is typed so the rest of the code reads `env.DATABASE_URL` instead of `process.env.DATABASE_URL!`.
Python
Safe JSON Read/Write
Idiomatic helpers for reading + writing JSON to disk, with atomic writes and pretty-printed output. Catches the common "edit and save → corrupt file on crash" failure mode.
Bash
Sum a Column with awk
Awk's default field splitter is whitespace; pass a single character with -F. Perfect for summing the Nth column of a log file or CSV.
Bash
Create User With Sensible Defaults
Provision a new user account with a home directory, default shell, and sudo membership. Idempotent — re-running on an existing user is a no-op.
PHP
Partition Array Into Two Buckets
Split an array into [matches, non-matches] using a predicate callback. Single pass, preserves order, returns two lists.
Go
time.Ticker — Periodic Tasks
`time.NewTicker(d)` fires on a channel every `d` interval. Combine with select + a done channel for a clean way to run periodic work that can be cancelled.
Go
maps package — Modern Helpers
`maps` (Go 1.21+) adds Keys, Values, Equal, Clone, Copy — replaces the slice-of-keys boilerplate you used to write to iterate a map deterministically.
TypeScript
invariant() — Always-On Assertion
Throw if a condition is false, with TypeScript narrowing the type afterwards. Replaces ad-hoc `if (!x) throw` ladders and gives you type-safe guards in one line.
Go
Custom Generic Constraints
Type constraints are interfaces with type sets. Use them to express "any numeric" or "any ordered" without resorting to `any`.
TypeScript
Discriminated Unions with Exhaustive Switch
Discriminated (tagged) unions give you compiler-checked state machines. Pair with `assertNever` to force every new variant to be handled at every switch site — refactors stop being scary.
PHP
Slack Incoming-Webhook Notification
Fire a quick notification to a Slack channel via an incoming webhook URL. Includes basic markdown-style mentions and an attachment color for severity.
TypeScript
Chunk Array Into Fixed-Size Pieces
Split an array into chunks of `size` items. Common building block for batch APIs — "send 50 rows per request" — and for paginated grids.
Kotlin
Local Functions
Functions can be declared inside other functions. Closures over outer scope let you eliminate parameter-threading. Use sparingly — too many nested locals hurts readability.
Bash
Pad String to Fixed Width
Pad strings left or right so columnar output lines up. printf gets you about 95% of what you need; the helpers wrap it for readability.