arr-helpers

Zero-dependency array helpers for frontend and backend — parse, group, chunk, sort, dedupe, and more.

Works in the browser (React, Vue, Next.js, Vite) and in Node (Express, Nest, APIs). Pure TypeScript, no Node-only APIs.

npm install arr-helpers

Quick start

import ArrayList, { chunk, uniqueBy, get, groupByField, paginate } from "arr-helpers";

// Parse query / form / URL values into arrays
get("1,2,3");           // ["1", "2", "3"]
get("[1,2,3]");         // [1, 2, 3]
ArrayList.getIntArray("1,2,3"); // [1, 2, 3]

// Chunk for UI lists or batch jobs
chunk([1, 2, 3, 4, 5], 2); // [[1,2],[3,4],[5]]

// Dedupe objects by key
uniqueBy(
  [{ id: 1, name: "a" }, { id: 1, name: "b" }],
  "id"
); // [{ id: 1, name: "a" }]

// Group rows (tables, charts, API payloads)
groupByField(
  [{ type: "a", v: 1 }, { type: "a", v: 2 }, { type: "b", v: 3 }],
  "type"
);

// Paginate for tables or API responses
paginate(items, 1, 20);

ESM and CommonJS:

import { chunk, isEmpty } from "arr-helpers";
// or
const { chunk, isEmpty } = require("arr-helpers");

Where it fits

| Frontend | Backend | |---|---| | Filter / sort / paginate UI lists | Normalize query params & body fields | | Group chart or table data | Chunk IDs for batch DB/API calls | | Dedupe options / tags | Aggregate and sum row fields | | Move items in drag-and-drop lists | Parse comma-separated IDs |

API

Core

| Function | Description | |---|---| | isEmpty / isNotEmpty | Empty-array checks | | isArray | Non-empty array check | | getLength | Safe length (0 for invalid) | | removeDuplicate / unique | Dedupe primitives | | uniqueBy | Dedupe by key or selector | | sort(data, key, "ASC"\|"DESC") | Sort objects by field | | stringIntoArray | "1,2,3" → [1,2,3] | | groupBy / groupByName | Sum quantities by date/name | | groupByField | Generic Record<key, T[]> | | groupByKey | Group by one or two keys | | splitArray / chunk | Split into sized batches | | mapByKey | Index objects by key | | mapByFilter | Filter by field, then pluck | | toArray | Wrap single value as array | | get | Normalize string/JSON/array input | | getIntArray | get + parse integers | | sumByKeys | Sum numeric fields across rows |

Extra helpers

| Function | Description | |---|---| | compact | Drop null / undefined / "" | | first / last | Safe ends with defaults | | pluck | Map a single field | | partition | Split by predicate | | difference / intersection / union | Set ops | | countBy | Count by key/selector | | maxBy / minBy / averageBy | Aggregates by field | | paginate(list, page, pageSize) | 1-based paging | | flatten | Flatten nested arrays | | moveItem | Reorder immutably | | shuffle | Fisher–Yates shuffle copy | | filterBy / findBy | Match by field value |

Why this package?

The same array patterns show up in UI lists and API services. arr-helpers packages them with zero dependencies, TypeScript types, tree-shakeable ESM, and CJS for older Node setups.

License

MIT