JS Standard Libraryv0.20.0

@opentf/std

The Modern JavaScript Standard Library.

A lightweight, high-accuracy, runtime-agnostic collection of essential utilities.

📦 Installation

Install @opentf/std using your preferred package manager:

bun add @opentf/std
pnpm add @opentf/std
npm install @opentf/std
yarn add @opentf/std
deno add @opentf/std

🚀 Quick Start

Beyond the everyday helpers, @opentf/std ships capabilities you'd normally reach for a separate package to get:

JavaScript
import {
  DateTime,
  Decimal,
  color,
  colorContrast,
  formatBytes,
  formatCurrency,
  uuidv7,
  stringWidth,
} from "@opentf/std";

// 🕒 Dates in any IANA zone — no time-zone database, no dependency
const t = new DateTime("2026-03-07T12:00", { timeZone: "America/New_York" });
t.add({ days: 1 }).format("HH:mm ZZ"); //=> "12:00 -04:00"  DST-safe: 23 real hours

// 🎯 Exact decimal math — no floating-point errors
new Decimal("0.1").add("0.2").toString(); //=> "0.3"

// 🎨 Color parsing, conversion & WCAG accessibility
color("rebeccapurple", "hex"); //=> "#663399"
colorContrast("white", "black"); //=> 21  (WCAG ratio)

// 💾 Human-readable, locale-aware formatting
formatBytes(1234567); //=> "1.18 MiB"
formatCurrency(1200, { currency: "EUR", locale: "de-DE" }); //=> "1.200,00 €"

// 🆔 Time-sortable UUID via runtime-agnostic crypto
uuidv7(); //=> "0195e2a4-8c3d-7000-…"

// 📏 Emoji & CJK aware string width (terminal-safe)
stringWidth("🔥こんにちは"); //=> 12

🧩 API shape

Arguments are named, not positional. Each function takes its primary input positionally, and everything else arrives in one final options object:

JavaScript
clamp(10, { min: -5, max: 5 }); //=> 5                  — (data, options)
pad("abc", 8, { chars: "_-" }); //=> "_-abc_-_"         — (data, secondary, options)
lerp({ start: 0, end: 10, progress: 0.5 }); //=> 5      — one object, no positionals
move([1, 2, 3], { from: 0, to: 2 }); //=> [2, 3, 1]

Three rules, applied everywhere:

  1. One primary input stays positional — the array, string, number or function being worked on.

  2. At most one secondary positional — length, limit, interval. A second setting onwards joins the options object.

  3. Peer values share one object — start/end/progress or from/to have no primary, so all of them are named.

Options are validated: passing anything that isn't an object throws a TypeError, and required keys (like set's { value } or pollRun's { until }) are enforced — a misspelled key fails loud instead of silently using the default.

👉 Next Steps

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