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JavaScript Memoize Function

Caches the result of a pure function keyed by its serialised arguments. On repeated calls with the same inputs the cached value is returned instantly, skipping expensive computation. Supports single and multi-argument functions via JSON key serialisation.

#memoize #performance #functional

@admin 9h ago

JavaScript Curry Function

Transforms a multi-argument function into a chain of single-argument functions. Each call returns a new function until all arguments are supplied, then the original function executes. Enables partial application and cleaner function composition pipelines.

#curry #functional #composition

@admin 9h ago

JavaScript Pipe & Compose

pipe applies a list of functions left-to-right (first function runs first), while compose applies them right-to-left. Both pass the result of each step as input to the next. Fundamental building blocks for functional programming in JavaScript — build data transformation pipelines without intermediate variables.

#pipe #compose #functional

@admin 9h ago

JavaScript Fetch with Retry

Wraps the native fetch API with automatic retry logic using exponential backoff. Retries on network errors or non-OK HTTP responses up to a configurable number of attempts. Exponential backoff with optional jitter prevents thundering herd problems when many clients retry simultaneously.

#fetch #retry #async #http

@admin 9h ago

JavaScript Async Sleep / Delay

Returns a Promise that resolves after a given number of milliseconds. Use with await to pause async functions without blocking the main thread. More readable than nested setTimeout callbacks and composable with other async utilities.

#async #sleep #delay #utils

@admin 9h ago

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.

#async #concurrency #promise #fetch

@admin 9h ago

JavaScript Event Emitter (Pub/Sub)

A lightweight publish/subscribe event system. Listeners register with on(), fire once with once(), are removed with off(), and events are dispatched with emit(). Useful for decoupling modules, building plugin systems, and implementing the Observer pattern without a framework dependency.

#events #pubsub #observer #pattern

@admin 9h ago

JavaScript Group Array by Key

Groups an array of objects into a map keyed by the result of a callback or property name. Uses Object.groupBy when available (ES2024) and falls back to a reduce implementation. Returns an object whose keys are the group names and values are arrays of matching items.

#array #groupby #utils

@admin 9h ago

JavaScript Flatten Nested Array

Recursively flattens an array of arbitrary nesting depth into a single flat array. Accepts an optional depth limit — pass Infinity to flatten completely. Uses the native Array.flat when the browser supports it, otherwise falls back to a recursive reduce.

#array #flatten #utils

@admin 9h ago

JavaScript Chunk Array

Splits an array into smaller arrays (chunks) of a specified size. The last chunk may be smaller if the array length is not evenly divisible. Useful for batch processing, pagination, rendering large lists in chunks, and rate-limited API calls.

#array #chunk #batch #utils

@admin 9h ago

JavaScript Unique Array Values

Returns a new array with duplicate values removed. The fast version uses a Set for primitives. The deep version supports deduplicating objects by a specific key, making it suitable for deduplicating API results or merged data sets.

#array #unique #dedup #utils

@admin 9h ago

JavaScript Shuffle Array (Fisher-Yates)

Randomly shuffles an array in-place using the Fisher-Yates algorithm, which produces a uniformly random permutation. Widely considered the correct way to shuffle — avoids the bias inherent in sort(() => Math.random() - 0.5). Returns the same array reference after shuffling.

#array #shuffle #random #utils

@admin 9h ago

JavaScript Debounce

Delays invoking a function until after a specified wait time has elapsed since the last time it was called. Essential for search inputs, resize handlers, and any event that fires rapidly — prevents excessive function calls and improves performance.

#debounce #performance #events

@admin 9h ago

JavaScript Pick & Omit Object Keys

pick returns a new object containing only the specified keys. omit returns a new object with the specified keys removed. Both are pure (non-mutating) and handle missing keys gracefully. Essential for cleaning API payloads, projecting data shapes, and avoiding over-sending sensitive fields.

#objects #pick #omit #utils

@admin 9h ago

JavaScript Flatten Object (Dot Notation)

Flattens a deeply nested object into a single-level object with dot-notation keys. Useful for comparing configs, building form field names from nested data, logging structured objects to analytics, or preparing data for flat key-value stores like Redis or environment variables.

#objects #flatten #utils

@admin 9h ago

JavaScript Format Currency

Formats a number as a locale-aware currency string using the built-in Intl.NumberFormat API. Supports any ISO 4217 currency code and any BCP 47 locale tag. No external library required — handles symbol placement, thousands separators, and decimal places automatically per locale rules.

#format #currency #intl #utils

@admin 9h ago

JavaScript Format Relative Time

Returns a human-readable relative time string ("3 days ago", "in 2 hours") using the Intl.RelativeTimeFormat API. Automatically selects the most appropriate unit (seconds, minutes, hours, days, weeks, months, years) based on the elapsed time. Fully localised — pass any BCP 47 locale.

#format #date #intl #utils

@admin 9h ago

JavaScript Format File Size

Converts a raw byte count into a human-readable string with the appropriate unit (B, KB, MB, GB, TB). Uses 1024-based (binary) units by default or optionally 1000-based (SI) units. Useful for upload progress indicators, file browsers, and storage dashboards.

#format #files #utils

@admin 9h ago